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
9
1
1
1
7
1
0
3
1
2
1
0
0
1
5
1
1
1
4
1
0
0
3
4
