okay so i feel like a dummie for not knowing this but i need the answer FAST!

Which property would allow you to use mental computation to simplify the problem 27 + 15 + 3 + 5?

1) commutative property of addition
2) distributive property
3) additive identity
4) additive inverse

Please help me

1 answer

They clearly want you to mentally group the numbers into
27+3 + 15+5 to quickly in your head find 20+20=40

Now which property lets you do something like
a+b = b+a ?