How do I find the sum of 3/7 and 1/21

Question

If possible I need an example on how this is worked out. I've been out of school for many years, plus I was never any good at math. Desperately trying to help my 5th grader with math homework.

Answer 1

i'm a 7th grader that took pre-algebra in the sixth grade, so i know what i'm doing.

first you need to ind a common denominator, so the easyest thing to do is take 3/7 and multiply it by 3/3, you will get 9/21.

then add 9/21 and 1/21, but only the top numbers.

you will get an final answer of 10/21.