The related number sentence that shows the commutative property addition for the equation 3+ 9 + 12 is 9 + 3 = 12
Please take note, the commutative property of addition is
a + b = c
b + a = c
a + b = b + a
Commutative originates from the word move around or commute, therefore, commutative property refers to the act of moving stuff around. In addition, the rule is a + b = b + a; wherein from the example above, means 9 + 3 = 3 + 9. They want to say that the computation uses the Commutative Property, if at any time, a computation depends on moving stuff around