Answer:
3 and 7
Explanation:
You know from your multiplication tables that ...
21 = 1×21 = 3×7
There are no other factorizations of 21 using integers. You may notice that the sums of these factors are ...
1+21 = 22
3+7 = 10 . . . . . . this is the pair of numbers you are looking for
The two numbers are 3 and 7.