P5 Vic Math E-Learning by Sook Hwa Goh

P5 Vic Math E-Learning by Sook Hwa Goh https://padlet.com/goh_sook_hwa/we7a8ir957d Revision en-us 2017-09-22 01:45:21 UTC 2023-09-01 15:48:33 UTC hello@padlet.com Let's get started. goh_sook_hwa https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/190021882 One example:
Topic: Solid Figures
Are you able to answer the following questions?

1. What are the two main types of solids?

Give at least 3 examples of each type.

2. List 2 properties of a prism.

3. Is a cylinder a prism? Explain your answer.
Check out this site
https://www.mathsisfun.com/geometry/solid-geometry.html

Mrs Tong

]]> 2017-09-22 07:45:18 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/190021882 Ryan Tan https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192753402 1) Pyramids and Prisms
Pyramids
Cone
Square-Base Pyramid
Triangle-Base Pyramid
Prisms
Cuboid
Cube
Octagonoid

2a) Two opposite faces are the same.
2b)Two opposite faces are connected by parallel lines

3) No. The two opposite faces are not connected by parallel lines.]]> 2017-10-01 12:41:28 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192753402 Matthew https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192753914 1)
square based and triangle based.
2)
both ends are the same
3)
no. it is not a polyhedra.]]> 2017-10-01 12:47:07 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192753914 Donovan donovankohmingen https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192823488 Topic: concept of infinity
Q1: What is the definition of infinity?

Q2: How does one calculate infinity(making use of its already existing cardinal value also known as aleph null)?

Q3: Why is the infinity symbol a figure eight like shape?

Answers:
Q1: Infinity is an abstract concept describing something without any bound or larger than any number.

Q2: since aleph null represents the largest possibility of infinity, we can then assume that aleph null is infinity and hence infinity is 1/x or if more mathematically accurate, 1/0 so infinity is 0 divided by one(this has been thoroughly debated over for years so please understand if you believe otherwise)

Q3: The infinity symbol, ∞, called the lemniscate is a mathematical symbol representing the concept of infinity. the symbol shows a line in a figure eight like pattern this represents infinite movement like how infinity(which is technically not a number but instead a representation of many numbers)has a never ending value.]]> 2017-10-01 23:55:50 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192823488 Yi Xun ChloeImposter https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192825377 Topic: Solid Figures

3. Is a cylinder a prism? Explain your answer.
There are arguments as to whether a cylinder is a prism.
Arguments that support:
1. When the shape is bisected, it becomes two cylinders. That is the same for other prisms, such as cuboids
2. A circle is a polygon with infinite sides (or polyhedron with infinite edges). Both opposite ends of a cylinder are bound by infinite parallel lines of the circle.
Arguments against:
1. A circle is not a polygon, and it has no sides (or it is not a polyhedron as it has no sides). Thus, opposite ends cannot be bound by parallel lines as there is no where to start and end.
--------------------------------
The real question is, " a circle a polygon?" "do circles have sides?" "do cylinders have edges?

]]> 2017-10-02 00:20:58 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192825377 Yi Xun ChloeImposter https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192826639 Topic: Angles
Remember to revise terms such as "supplementary angles", "complementary angles", "alternate opposite angles".

Supplementary Angles are two angles that add up to 180°. (e.g. angles 1 and 4)
Complementary Angles are two angles that add up to 90°.

Angles 2 and 8 are alternate interior angles and thus are congruent. They are marked with red.
Angles 3 and 8 are interior angles and are marked with blue. These angles arealways complementary.
Angles 3 and 7 are alternate angles and always correspond to each other. These angles are congruent and are marked with yellow.
Each of them are shaped like a letter: Alternate interior is haped like

]]> 2017-10-02 00:38:19 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192826639 Tiffany https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192826987 Topic: Geometry
Q1: What are the formulas for calculating the area of rectangles, triangles, trapeziums and parallelograms?
Rectangles: length x breadth
triangles: 1/2 x base x height
trapeziums: 1/2 x length of 2 parallel sides x height
parallelograms: length x height
Q2: How do we calculate the volume of 3D objects?
For cubes and cuboids, the formula is length x breadth x height.
Q3: How do we calculate angles in 2D shapes?
the total degree of angles in a triangle is 180°, 360° in 4-sided figures. In figures with more sides, add 180° x (no. of sides-4) to 360°. For example, for 5-sided figures, add 180° to 360°, for 6-sided figures, add 180°x2 to 360° and so on.]]> 2017-10-02 00:41:55 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192826987 Zhining https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192827517 Topic: Volume and Solid Figures
Q1 : How do we find the volume of an object (cuboid)?
Q2 : How many cubes are there is this figure? (at bottom)
Q3 : Is a cuboid a cube? Is a cube a cuboid?]]> 2017-10-02 00:48:18 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192827517 Dominic dominic_nyh https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192827700 Topic: Area
To find out the area of n- sided polygon, take the number of sides(n) - 2. then multiply it by 180 degrees.]]> 2017-10-02 00:50:36 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192827700 Grace Tan https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192827729 Topic: Solid Figures, Volume and Surface Area
Q1: What is the base design of a solid figure?
Q2: How can you calculate the dimensions of a box when only the areas of its faces are given?
Q3: How can you find the height of the water level of a container, B, when another container, A, is filled to the brim then some water from A is transferred to B until the water level in both containers is the same? (e.g. WS 146, Q13)
Answers:
Q1: The base design of a figure is the top view of the solid figure with numbers indicating the number of cubes stacked at each position in the solid figure's base.
Q2: You can find the common factors of those areas. (interesting tip: if the question asks for the volume, but not the dimensions, you can definitely use the method above by just multiplying the dimensions because l x b x h = volume, but an easier and quicker method is to multiply the areas of the faces, then square that number, e.g. the faces are: 32, 56, 28, then, 32 x 56 x 28= 50176, then, square 50176, you will get 224[which is the answer], as mentioned, 224 is also the sum of the dimensions: 8x4x7, which are the common factors of 56, 28, 32)
Q3: You can find the ratio of the base areas of A and B, add them up, divide the volume of water by that, then multiply that number by A's number, and then divide that by the base area of A
E.g. Vol. of water= 10 x 14 x 8 = 2520
A : B
160: 140
8 : 7
8 + 7 = 15
2520 ÷ 15 = 168
8 x 168 = 1344

1344 ÷ 160 = 8.4 Ans: 8.4 cm
Surface area tip: if you have to: calculate the surface area of an irregular solid figure, just find the area of one face, then find the number of faces on the top, front, and right, and multiply it by the area of one face then by 2 to get the surface area
E.g.

Area of one face = 1 x 1
Front: 8
Top: 16
Right: 12
(8+16+12) x 1 x 2 = 72
Surface area: 72 cm ²

]]> 2017-10-02 00:50:56 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192827729 Yi Xun ChloeImposter https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192829014 Figure 1
The lines with 4 vertices each are parellel]]> 2017-10-02 01:02:44 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192829014 Zhining https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192831738 Answers:
Q1 : Length x Breadth x Height / L x B x H / L by B by H
Q2 : 22 cubes ( count systematically from top to bottom to get accurate answers)
Q3 : 1 . No. A cuboid does not have all equal sides like a cube / does not have the same properties as a cube.
2. Yes. A cube has all the same properties as a cuboid
]]> 2017-10-02 01:30:48 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192831738 Hayden haydenlim24 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192831835 Topic: Area, surface area, and solid figures
Q1:
a)How do you find the area of a cube?
b) How do you find the surface area of a cube?
Q2:

a)How do you find the area of a cuboid?
b) How do you find the surface area of a cuboid?
Q3:
Look at the drawing below. How many more cubes are needed to form a cube?

]]> 2017-10-02 01:31:58 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192831835 Ong Boon Yang whatandwhy888 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192837312 Topic: Properties of different quadrilaterals

1) A quadrilateral is a 4-sided polygon with no distinct feature 2)Parellelogram is a quadrilateral that has two pairs of parallel lines FORMULA(AREA): LxB 3)Trapezium is a quadrilateral with only 1 pair of parallel lines. FORMULA(AREA): (Sum of two parallel lines)/2 x H
4)Rhombus is a kite which has two pairs of parallel lines and all sides are equal FORMULA(AREA): [Lets name 1 diagonal p and the other q] p x q/2
5)Kite is a quadrilateral that adjacent sides are equal and the diagonals form 90 degrees
FORMULA(AREA): 1/2 x (product of the 2 diagonals)
6)Rectangle is a parallelogram which opposites sides are equal and parallel and all angles are 90 degrees
FORMULA (AREA): L x B
7) Square is a rectangle which all sides are equal
FORMULA(AREA): L x L or B x B]]> 2017-10-02 02:21:33 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192837312 Hayden haydenlim24 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192838330 Answers:
Q1:
a)LxLxL All the sides are the same length so we only need one measurment cubed to get the volume.
b)LxLx6 Here we are find the exposed surface area of one side of the cube and as a cube as 6 sides, we multiply by 6.
Q2:
a)LxBxH A cuboid may have three different sides so we need three measurments multiplyed to get the volume.
b)(LxBx2)+(HxLx2)+(BxHx2)
Here we find the exposed surface area of the Top and bottom which is LxB and there are two sides so we multiply by two. Next, we find the exposed surface area of the sides and that is HxL and then multiply by two as there are two sides. Last of all, we find the exposed surface area of the front and back which is BxH and then multiply by two because there are also two sides.
Q3: 64-15=49
Extra info (enrichment)
Area of eclipse: Find the shortest length from the middle to edge. Let's call this A. Next, find the longest length from middle to edge. Let's call this B.
Now, take AxBx3.14(which is pi) and you will get the answer.
Understanding how this works:
Area of circle=PIxRxR. Lets say we take a circle, squash it, and get a eclipse. Nothing leaves the eclipse, so the area will remain the same. One side will become longer and the other shorter, and they will cancel each other out. In theory, if we add AxB(of the eclipse from the squashed circle) it equals to RxR(of the circle before we squashed it). So, you will get the same answer if you take AxBxPI and if you take RxRxPI. In the fomula, we are just replacing R and R with A and B.

]]> 2017-10-02 02:32:37 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192838330 Solid Figures enkl9806 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192838817 1. What are the two main types of solids? Give at least three examples of each type.
My response: Polihedra Solids and Non-polihedra Soilds
Polihedra Solids - Cubes, Cubiods and Triangle-based Pyramids.
Non-polihedra Solids - Sphere, Torus, Cylinder.
(https://www.mathsisfun.com/geometry/solid-geometry.html)

2. List two properties of a prism.
My response: A prism is a solid object with identical ends and flat faces.
(https://www.mathsisfun.com/geometry/solid-geometry.html)

3. Is a cylinder a prism? Explain your answer.
My response: A prism is a polyhedron, therefore, all of its faces are flat. It will not have any curved sides. A cylinder is not a prism, because it (the cylinder, not the prism) has curved sides]]> 2017-10-02 02:38:30 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192838817 Jonas SuRf26 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192838914 Calculating areas and volumes of different objects as well as other interesting information ( ͡° ͜ʖ ͡°)
-------------------------------------

2D OBJECTS
1. Square
Area formula: Length²
Perimeter formula: Length x 4
2. Triangle
Area formula: 1/2 x Breadth x Height
Perimeter formula: Formula (too lazy to write)
3. Circle
Area formula: πr²Perimeter formula: 2πr
4. Rectangle
Area formula: Length x breadth
Perimeter: length x 2 + breadth x 2
5. Kite
Area formula: D₁ x D₂ ÷ 2*
*Diagonal 1 and Diagonal 2
Perimeter: Formula
6. Parallelogram
Area formula: Base x Perpendicular height
Perimeter: Formula
7. Trapezium
Area formula: [Base + Parallel Base (Line that is parallel to base)] ÷ 2 x perpendicular height

Perimeter: Formula
-------------------------------------
3D OBJECTS
1. Cube
Volume formula: Length³Sides: 6
Test
2. Cuboid

Volume formula: length x breadth x height
Sides: 6
Test
3. Pyramid
Volume formula: (Base width x Base length x Pyramid height)÷3
Sides: 4 or 5
Test
4. Prism (Triangular)
Volume formula: Area of base x perpendicular height.
Sides: 5
Test
5. Cylinder
Volume formula: Area of base x perpendicular height
Sides: NA
Test
6. Sphere
Volume formula: 4/3 πr³Sides: NATest

]]> 2017-10-02 02:40:08 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192838914 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192839669 2017-10-02 02:49:47 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192839669 Xinning Volume & Surface Area https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192840284 1. What is an edge?
Ans: An edge is where two faces meet.
2. What is the difference between a prism and a pyramid?
Ans: A prism is a figure made of congruent shapes but a pyramid is made of shapes that get smaller.
3. What is the formula for volume of cubes and cuboids?
Ans: *Length x Breath x Height.
*Length x Breadth is the area of a cross section
4. What is a polygon and a polyhedron?
Ans: A polygon is a 2-D shape and a polyhedron is a 3-D shape.]]> 2017-10-02 02:57:00 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192840284 Javier https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192840769 Topic: Fractions
1. How do you multiply or divide fractions together?
Ans: Multiplication

Multiply the numerators of the fractions to get the new numerator.
Multiply the denominators of the fractions to get the new denominator.

Division

Leave the first fraction in the equation alone.
Turn the division sign into a multiplication sign.
Flip the second fraction over (find its reciprocal).
Multiply the numerators (top numbers) of the two fractions together. ...
Multiply the denominators (bottom numbers) of the two fractions together.

]]> 2017-10-02 03:02:19 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192840769 Lionel Goh https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192847828 https://www.youtube.com/watch?v=gHYoTzSx2gs
The units and parts method
Its very tedious but useful
It can be applied for almost any whole noumber question
I'll be back with more]]> 2017-10-02 04:16:53 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192847828 Ju XiangQi novaFractal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192847908 Topic: Whole Numbers

I observed the pattern that the difference between two consecutive perfect squares (the larger expressed as n) is the nth odd number (2n-1). For example, 1 - 0 = 1. 4 - 1 = 3. 9 - 4 = 5, and so on.
By any chance the exam question asks you to find (one of/the sum of) two perfect squares which differs by x, this method is easier and more efficient than guess and check. ]]> 2017-10-02 04:17:29 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192847908 Lionel Goh https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192848328 https://www.youtube.com/watch?v=OanPzjf2EYY
A more basic volume question I'll be back with more

]]> 2017-10-02 04:22:53 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192848328 Discussion on whether a circle should be considered a polygon (posted by Ju XiangQi novaFractal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192848520 A circle is formed by joining infinite straight lines, and a sphere is formed by infinite flat surfaces. By this explanation, a circle should be considered a polygon.
But should a circle be considered a polygon, all other shapes drawn (including those with curved lines and unevenly distributed curved lines) should be considered a polygon too. But what will be the point of having such a definition as polygon where polygon = (any) shape?
Anyways, should there such n-sided shapes be considered polygons where n = infinity?]]> 2017-10-02 04:25:35 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192848520 (Ewan) Topic: Whole Numbers ewanyong2006 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192852470 Solving this without mistakes.
10+2x(3x5+1)+1
1. First, look in the brackets (If there are brackets. If there are no brackets then look at the bottom part). If there are "power signs" (eg. 3 to the power of 4) do those first. (left to right) Then, if there are multiplications and division in the brackets, do those next. (remember, left to right if there are more than one of the Multiplication and Division signs). Then, do addition and subtraction (still in the bracket). After that, look for "power signs" on the brackets (eg 3 to the power of 4).
Then, follow the above steps, but without the brackets. It really helps to record down the answers to seperate equations, so as to not forget. (Not really tips and tricks, just prevention of careless mistakes.)

]]> 2017-10-02 05:13:11 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192852470 Bryan Kow https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192853161 Topic: Percentage

1. 0.01% is NOT equivalent to 0.01. If you see a % at the back of a number or decimal, you have to divide that number or decimal by 100 to get the actual value.]]> 2017-10-02 05:22:27 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192853161 Jonas Lim SuRf26 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192855714 ----------------------------------------------------
Shortcuts and life hacks for Math ( •_•)
| ( •_•)>⌐■-■
| (⌐■_■)
----------------------------------------------------
1. a% of b is b% of a.
At first it doesn't really make any sense at all but when you split it up like this:
1/100 x b x a = b% x a
1/100 x a x b =a% x b
1/100 x b x a = 1/100 x a x b
∴(Therefore) b% x a = a% x b!
----------------------------------------------------
2. Multiplying two digit numbers by 11
Multiplying by 11 is tricky by problem sums, but technically there are two ways that you can learn how to multiply by 11.

a. The trickier way.
If you want to find what is 52 x 11, you can do it like this:
52 x 10 = 520
This step is simple because you just need to add a zero at the back.
520 + 52 = 572
This step is not tricky, but easy to make careless mistakes on. For larger numbers such as 75 and 98, this might be slightly more tricky.

b. The easier and cooler way.
Another way to find out 52 x 11 is to do it this way:
Take the two digits of the number you want to multiply and add them together.
5 + 2 = 7
Now that you have gotten 7, insert it between the two digits and you get 572. Which is the answer.
Oh, but this becomes trickier when it comes to different numbers. For example, what is 57 x 11?
Ok, so let's repeat the process again.
5 + 7 = 12.
Oh no, this number has more than one digit! What do we do?
Simple. First we take the last digit of this number. In this case, it is 2. But remember: DON'T DISCARD THE FIRST DIGIT! IT WILL BE OF MUCH USE LATER.
Before that, let us slot in 2 in between 5 and 7. We should get 527. But this doesn't make sense! So here is where the first digit comes into use. Combine the first digit (1) with the digit to the left of the number you have just slotted in. That digit should be 5. So here's what we do.
5 + 1 = 6
The digit which was on the far left of the number was 5, so it will be replaced by the new digit: 6!
So here's our final answer: 627!
But when it comes to another number, take for example 99 x 11. When you reach the second step, you will realise that 9 + 1 is not a 1 digit number. In this case, still do the same thing but retain the number 1. So in this case, you should get: 1089. And this is the correct answer.
----------------------------------------------------
I'll be back with more!]]> 2017-10-02 05:52:04 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192855714 Mental Sums https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192865303 1. Subtracting from 1,000

Here’s a basic rule to subtract a large number from 1,000: Subtract every number except the last from 9 and subtract the final number from 10

For example:

1,000 – 556

Step 1: Subtract 5 from 9 = 4

Step 2: Subtract 5 from 9 = 4

Step 3: Subtract 6 from 10 = 4

The answer is 444.
To check, type the equation into your calculator. Do you get 444?

2. Divisibility Test recap

10 if the number ends in 0
9 when the digits are added together and the total is evenly divisible by 9
8 if the last three digits are evenly divisible by 8 or are 000
6 if it is an even number and when the digits are added together the answer is evenly divisible by 3
5 if it ends in a 0 or 5
4 if it ends in 00 or a two digit number that is evenly divisible by 4
3 when the digits are added together and the result is evenly divisible by the number 3
2 if it ends in 0, 2, 4, 6, or 8

3. Multiplying 5 times any number

When multiplying the number 5 by an even number, there is a quick way to find the answer.

For example, 5 x 4 =

Step 1: Take the number being multiplied by 5 and cut it in half, this makes the number 4 become the number 2.
Step 2: Add a zero to the number to find the answer. In this case, the answer is 20.

When multiplying an odd number times 5, the formula is a bit different.

For instance, consider 5 x 3.

Step 1: Subtract one from the number being multiplied by 5, in this instance the number 3 becomes the number 2.
Step 2: Now halve the number 2, which makes it the number 1. Make 5 the last digit. The number produced is 15, which is the answer.

These can be used for division as well.
By Claudia Lim

]]> 2017-10-02 06:50:57 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192865303 William https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192892931 How to multiply a number by 11

There is an easy trick for multiplying any two-digit number by 11.
For example:

11 x 25

Take the original two-digit number and put a space between the digits. In this example, that number is 25.

2_5

Now add those two numbers together and put the result in the center:

2_(2 + 5)_5

2_7_5

The answer to 11 x 25 is 275.

If the numbers in the center add up to a number with two digits, insert the second number and add 1 to the first one. Here is an example for the equation 11 x 88

8_(8 +8)_8

(8 + 1)_6_8

9_6_8

The answer is 968.

]]> 2017-10-02 08:46:23 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192892931 N-sided figures https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192906617 Jvan
To find the total of the angles in a n- sided figure,you split the figure into the minimum no. of triangles.Then, you multiply the number you get by 180 degrees.e.g. A rectangle splits into a minimum of 2 triangles. 2 x 180 degrees =360 degrees . This is correct as 90 degrees x 4 is also 360 degrees.]]> 2017-10-02 09:41:17 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/192906617 More Mathematics Life Hacks with Jonas AKA SuRf26 😵😵😵 SuRf26 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193294173 Hey everybody! Welcome back to more MATH HACKS with me.
----------------------------------------------------
1. Calculating fractions in literally one second
First let's get two random fractions: 3/4 & 2/5.
So, what is 3/4 + 2/5?
Could you do it without the calculator or in less than one second? I would think not. But there is a way!
We have ¾ and ⅖. Ok, let's take the first fraction's numerator (the number on top) and the second fraction's denominator (the one below) and multiply them together:
3 x 5 = 15
Now let us repeat this step with the first fraction's denominator and the second fraction's numerator.
2 x 4 = 8
Alright, now let us multiply both the denominators together.
5 x 4 = 20
So now we add 15 and 8 together. You should get 23. Then we take 23 and put it on top of 20. Now, you should get the fraction: ²³/₂₀. If we put it into mixed numbers, we should get 1³/₂₀. And that is the answer! If you doubt me, check with Mr. Calculator.
If you want to subtract the two fractions instead, just flip the addition sign to a subtraction sign when you are adding 15 and 8 together and you should get 7. So the answer is ⁷/₂₀. Simple!
----------------------------------------------------]]> 2017-10-03 07:31:23 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193294173 EVEN MORE Math Hax with Jonas ლ(ಥ Д ಥ )ლ SuRf26 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193302836 Just a continuation of my previous math hacks.
----------------------------------------------------
2. Calculating the day of any and ANY date

Take the last 2 digits of the year. In our example, this is 82.
Divide by 4, and drop any remainder. 82 / 4 = 20, remainder 2, so we think "20."
Add the day of the month. In our example, 20 + 16 = 36.
Add the month's key value, from the following table.

Jan - 1
Feb - 4
Mar - 4
Apr - 0
May - 2
June - 5
July - 0
Aug - 3
Sept - 6
Oct - 1
Nov - 4
Dec - 6

The month for our example is December, with a key value of 6. 36 + 6 = 42.
If your date is in January or February of a leap year, subtract 1. We're using December, so we don't have to worry about this step.
Add the century code from the following table.

1700s - 4
1800s - 2
1900s - 0
2000s - 6

Our example year is 2482, and the 2400s aren't in the table. Luckily, the Gregorian calendar repeats every four hundred years. All we have to do is add or subtract 400 until we have a date that is in the table. 2482 - 400 = 2082, so we look at the table for the 2000s, and get the code 6. Now we add this to our running total: 42 + 6 = 48.
Add the last two digits of the year. 48 + 82 = 130.
Divide by 7 and take the remainder. This time, 1 means Sunday, 2 means Monday, and so on. A remainder of 0 means Saturday. 130 / 7 = 18, remainder 4, so December 16, 2482 will be on the fourth day of the week-- Wednesday.

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]]> 2017-10-03 08:06:23 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193302836 Ryan Tan mozartseal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193418789 (This is related to Donovan's earlier post)
Infinity Sign = Mobius strip = Loop = Cannot end = Incalculatable = A Concept]]> 2017-10-03 13:41:54 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193418789 Ryan Tan mozartseal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193427391 A Mobius strip:]]> 2017-10-03 13:55:08 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193427391 Math HAX (A new day) ▬▬ι═══════ﺤ ／人 ◕ ‿‿ ◕ 人＼ SuRf26 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193735751 More math HACKS EVERY DAY!!!!!
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1. Calculating the square of any two digit number that ends with 5.
Let's take 35²for example.
Firstly, take the digit on the left. In this case, it is 3.
Add 1 to this number.
3 + 1 = 4
Then take this new number and multiply it with the original number, like this.
4 x 3 = 12
The answer is 12.
Now let's take the whole 35. Take 10 away from it.
35 - 10 = 25
The answer is 25. Combine this number with 12 and you get 1225. And that is the answer.
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2. Easy multiplication by 4

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]]> 2017-10-04 07:45:03 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193735751 Faith https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193828519 I wrote something about triangles and now it is gone]]> 2017-10-04 13:04:10 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/193828519 Math HAX (Another Day!!!)ᕕ( ᐛ )ᕗ SuRf26 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/194181875 1.

3.

]]> 2017-10-05 07:39:36 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/194181875 MATH HAX SuRf26 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/194875961
Find the cube root without a calculator

Ok here we go, something a bit more complex. If you want to find the cube root of a number you'll only need to remember the cubes of 1 to 10. You will need to take the last digit of your number, this will be the last digit of the result. Next, you ignore the last three digits. After that, you look at what you have left and find which of the beginning 10 instances of cubes is the closest to the remaining numbers (as a number). Now combine your answers to get the result. Confused? Let's use an example.

Let say you want to find the cube root of 39,304.

Step 1 = Strip the 4 of the end, this is the last digit of your answer.

Step 2 = Now ignore the last three digits, including step 1 above (except for it being the last digit of your answer). This will leave 39.

Step 3 = Now cube the 3 and the 9.

3 x 3 x 3 = 27

9 x 9 x 9= 729

As we are left with 39 from our answer in step 2, 3 cubed is the closest to 39.

Step 4 = Now take the 3 and the 4 and combine (not add) to get your answer. So the cube root of 39,304 is 34! Bingo!

]]> 2017-10-07 03:43:32 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/194875961 MATH HAX SuRf26 https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/194876232 32 degrees Celsius = ? degrees Fahrenheit

(32 x 1.8) + 32 = ? Fahrenheit

57.6 + 32 = ? Fahrenheit

32 degrees Celsius = 89.6 degrees Fahrenheit

]]> 2017-10-07 03:51:55 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/194876232 Faith Leong https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/196282090 The number π is a mathematical constant. Originally defined as the ratio of a circle's circumference to its diameter, it now has various equivalent definitions and appears in many formulas in all areas of mathematics and physics.]]> 2017-10-12 05:04:16 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/196282090 Martin martinquah https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/197005463 Topic: Volume
Always remember, the way to find the volume of a solid figure (e.g cuboid) is take its length, multiply it by its breadth then multiply again by its height.]]> 2017-10-14 08:11:10 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/197005463 Martin martinquah https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/197005933 Topic: Volume
To find out how many cubes you can put in one big cuboid, you do not simply find one of the cubes' volume and divide the cuboids volume by it. Instead, you find out how many cubes can occupy the breadth of the cuboid. (e.g 21 divided by 2, which means 10 cubes can occupy the breadth of the cuboid, as remainders are not counted.) Then, you multiply it by how many cubes can fit in the length. There, you should find your answer. ]]> 2017-10-14 08:18:11 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/197005933 Angles https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/197116959 Faith Leong
The lines are straight and parallel
Corresponding angles

See how it looks like an 'f'
Interior angles:

See how it looks like a 'U'
Alternate angles:

See how the it looks like a 'Z'

Vertically opposite angles

Looks like an 'X'
Gawd now all the diagrams are gone]]> 2017-10-15 14:25:26 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/197116959 How to multiply an even number by 5 novaFractal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/198077165 It have been a while since I last posted something, and I have something to share. I have been using this method for a long time and it is much more convenient than having to use some vertical working or the calculator.

Multiplying an even number (abcd) by 5:

Get abcd divided by 2
Add a '0' behind

And we're done!

Actually, this method does not require you to write the whole thing out. It is best to use mental calculation for these steps.

Example:
Random number: 1234

1234 * 5
1234/2
= 617
617 * 10
= 6170.
Thus, 1234 * 5 = 6170.
A simple proof:
5x = x / 2 * 10
_{Note: These methods were not sourced online and I came up with it myself while I was doing math.
-------All credits to me! -------}

]]> 2017-10-18 02:20:39 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/198077165 In the same way, let us now divide a number with a '0' behind by 5. novaFractal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/198078457 In the previous Padlet post, I have shared the method to use to multiply an even number by 5. Using the same logic, you can divide a number, for example, pqrs0, by 5.

Multiply pqrs by 2
(Forget about the '0' and don't add it back.)

And we're done!
Example
Random number: 987650
987650 / 5
98765 * 2
= 197530
Thus, 987650 / 5 = 197530
_{Note: These methods were not sourced online and I came up with it myself while I was doing math.
-------All credits to me! -------}

]]> 2017-10-18 02:31:31 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/198078457 novaFractal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/198079664 Dear Mrs Tong and classmates, take note that I (TheUltimateFactorial) am XiangQi. ]]> 2017-10-18 02:42:36 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/198079664 Ruuhan https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/199231288 How to manage time properly during maths exam:
Paper 1: 15-20 min on first 20 qns
2

]]> 2017-10-21 01:19:18 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/199231288 Divide a number with 5 behind by 5 novaFractal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/199445038 Previously I shared about dividing numbers with 0 behind by 5. It seems that there is no method to divide a number with 5 by 5 using that logic but there is.
Divide a number (abcd5) by 5:

Ignore the 5 behind
Multiply abcd by 2
Add 1 to the result in step 2

And we're done!
Example:
Random number 8765
876 * 2 = 1752
1752 + 1 = 1753
Thus, 8765 / 5 = 1753
_{Note: These methods were not sourced online and I came up with it myself while I was doing math.
-------All credits to me! -------}

]]> 2017-10-23 05:01:12 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/199445038 Do not forget to write the word statements for paper 2! novaFractal https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/199445654 For section 1 in paper 2, just write the word statements to be safe. ]]> 2017-10-23 05:09:14 UTC https://padlet.com/goh_sook_hwa/we7a8ir957d/wish/199445654