Question #0172a

1 Answer
Oct 10, 2017

A rational number "is any number that can be expressed as the quotient or fraction p/qpq of two integers, a numerator pp and a non-zero denominator qq. Since qq may be equal to 11, every integer is a rational number" (Wikipedia).

Explanation:

The numbers given to us have a bar on the top. In case you don't know what that means, if we translate number 2121 we get this:

-0.11111111111111...(extending until infinite 1's)

So, is this a rational number? Yes, because you can (as the definition from Wikipedia states), -0.1111111111111111... can also be expressed as the fraction -1/9, where p=-1 and q=9.

Similarily, you will find number 22 to also be expressed as a fraction. I will not show the process here because you probably get the point.

Therefore, both number 21 and 22 are rational numbers.

I hope that helps!