explain how knowing 1+7 helps you find the sum for7+1

+1

(1) Answers

HELPPLZ36

1+7 and 7+1 are the same equations. The numbers are just switched around .
Example:
1+2=3
2+1+3
They add up to the same answer no matter where they are placed, therefore knowing 1+7 helps you find the sum of 7+1 (again, because they are the same)