Question

Which statement shows the associative property of addition?

(+7)+ 13 = U+ (7 + 13)
21+2y=2y+21
if m+ 3 = 18 then 18 = m + 3​

Answer 1

the first one is the correct answer i.e.

(+7) + 13 = U+ (7+13)

Answer 2

It should be the first one since your changing the grouping.