Question

Two different ways to find the difference for 12-3

Answer 1

12-3=9
9+3=12
12-9=3

I hope this helped!

Answer 2

For this case we have:

 way 1:
 Common factor 3 in the expression:
 $12-3 = 3 (4-1) 12-3 = 3 (3) 12-3 = 3 (9)$

 Way 2:
 Write the number 12 as the sum of 4 times 3:
 $12-3 = (3 + 3 + 3 + 3) - 3$
 Then, for associative property:
 $12-3 = 3 + 3 + 3 + (3 - 3) 12-3 = 3 + 3 + 3 + (0) 12-3 = 3 + 3 + 3 12-3 = 9$