71-45 = subtracting by adding up

To do this, first you take the smaller number and add up till you reach a land mark number. A good landmark number is a number closest to the bigger number in the multiples of 10. Then you take that landmark number and add up to the bigger number. The answer would be the sum of the numbers you used.

71 - 45

45 + 25 = 70 (Landmark number)

70 + 1 = 71

Add up the numbers you "used"

25 + 1 = 26