Answer:
The associative property of addition.
Step-by-step explanation:
The associative property basically says that it doesn't matter if you add y to 3 + m or you add m + y to 3; you'll come out with the same answer in both cases. Put another way, it tells us we can group terms however we want, and it won't effect the outcome. For another example, (3 + 5) + 4 = 3 + (5 + 4) -- it doesn't matter whether we start with 3 + 5 or 5 + 4. The associative property is why we're allowed to write addition without parenthesis.
