2
2Keywords:
addition
additive identity
commutativity
inverse
properties of zero
subtraction
Students use the additive identity and the commutative property to assist them to solve simple equations without calculating.
2
1
1
9
13
4
7
8
5
2
1
1
3
2
4
6
1
4
0
2
2
1
3
2
8
