# Khan/khan-exercises

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 Properties of numbers 2
randRange( 1000, 9999 )

NUM \times 1 =

NUM

Any real number multiplied by 1 equals itself.

Without performing any multiplication steps, we know that NUM \times 1 = NUM.

This fact about multiplying by 1 is known as the identity property of multiplication, and it is useful for finding equivalent fractions.

NUM + 0 =

NUM

Any real number plus 0 equals itself.

Without performing any addition steps, we know that NUM + 0 = NUM.

By what number can we multiply NUM to get 1?

1 / NUM

Any real number x (except 0) can be multipled by \dfrac{1}{x} to get 1.

Without performing any multiplication or division, we know that NUM \times \dfrac{1}{NUM} = 1.

This fact about multiplying by \dfrac{1}{x} is known as the multiplicative inverse property.

What number can we add to NUM to get 0?

-1 * NUM

Adding the negative inverse of a number to that number equals 0.

Without performing any addition or subtraction, we know that NUM +(-1 * NUM) = 0.

Thus, the answer is -1 * NUM.