Question

50-20 = 30
30-15 = 15
15-9 = 6
6-6 = 0
If you were to check your work, you would get 51. What did I do wrong???

Answer 1

You did everything correctly! I did it myself...all of your subtraction is correct, then I added the answers together and I got 51. Where you trying to get another answer?

Answer 2

You should sum the answers and see: 30 + 15 + 6 = 30 + 10 + 5 + 6 = 40 + 5 + 5 + 1 = 50 + 1 = 51.