Answer:
12+(9+20)
(20+9)+12
9+(20+12)
(9+12)+20
Step-by-step explanation:
The associative property of addition is saying that if three or more numbers are added, the answer won’t change if you add or move parentheses.
So if the question is 1+2+3, the answer will be the same even if you write it as (1+2)+3 or 1+(2+3) or 2+(1+3) and so on.