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Learn for free about math, art, computer programming, economics, physics, chemistry, biology, medicine, finance, history, and more. Khan Academy is a nonprofit with the mission of providing a free, world-class education for anyone, anywhere.

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Well, before this starts to sound like a Zen koan, let's look at how we use the numeral "0." Arab and Indian scholars were the first to use zero to develop the place-value number system that we use today. When we write a number, we use only the ten numerals 0, 1, 2, 3, 4, 5, 6, 7, 8, and 9.

# data[].attributes.attachment_link.description
Learn more about the real number system. Understand more about rational, irrational, whole, and natural numbers. Make sure you are ready for your exam.