How do you simplify the fraction #3/21#?

1 Answer
Dec 1, 2016



Find the greatest common factor of each term.

3 is a prime number, so in this case, 1 or 3 are the only valid candidates. 1 is not helpful though, so it is discarded.

Try dividing 21 by 3. If you get a whole number, it works. If you do not, that means you cannot simplify the fraction in the first place. If you get a whole number which is not a prime number and the numerator is not a prime number, it means you can simplify it further still.

In this case, 1 cannot be simplified further.

#3 / 3 = 1#

#21 / 3 = 7#

7 is a prime number as well.

Therefore, the answer is #1/7#.