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Operations and Algebraic Thinking 1.0A:

Work with addition and subtraction equations-

Determine the unknown whole number in an addition or subtraction equation relating three whole numbers.

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Find the missing addend or missing number in an addition equation.

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Students will be able to determine the missing addend in an addition equation using three ways of instruction: number bond, subtraction, and number sense.

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Basic Tier- Know numbers 1-10, have little number sense, benefit from using number bonds and illustrations to figure out the solution to the equation.

Intermediate Tier- Know numbers 1-15, have some number sense, and can use subtraction as a means to work backwards and find the solution to the equation.

Advanced Tier-Know numbers 1-30, have quick number sense and can identify the missing addend using their number sense.

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Find the missing addend in the addition equation.

1. 6 + __ = 10

2. 10+ __= 20

3. 15+ __= 30

Students in the advanced tier will be able to answer the three problems using their number sense, working backwards using subtraction, or using a number bond. This is an open ended problem as they can solve it using multiple ways.

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Find the missing addend in the addition equations.

1. 4 + __ = 10

2. 6+ ___= 9

3. 3+ ___ = 6

The intermediate tier is able to solve this open ended problem via two methods, through subtraction or through the use of a number bond to get their solution.

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Find the missing addend or missing number in the addition equations.

1. 2+ __= 5

2. 3+ __= 6

3. 4+ __= 8

In the basic tier, students are able to answer the three questions above using number bonds and visuals.

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Students use their knowledge on number sense to answer the following questions.

1. 6+4=10

2. 10+ 10=20

3. 15+ 15=30

Students use comprehension and prior knowledge to know the missing addends.

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Students use their prior knowledge on subtraction to solve for the missing addend through the use of visuals.

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Students use their knowledge on number bonds and using visuals to find the missing number.