Use subtraction:
80 - 25:
Line up our numbers vertically:
| 8 | 0 | |
| _ | 2 | 5 |
| 10 | ||
| 8 | ||
| _ | 2 | 5 | 5 |
Column 1:
0 - 5 is < 0, we need to borrow 10.
Column 1: 10 + 0 - 5 = 5
| 7 | 10 | |
| _ | 2 | 5 | 5 | 5 |
Column 2:
Since we borrowed on the last column, we take it out of 8
Column 2: 8 - 1 - 2 = 5
Final Answer
Answer = 80 - 25 = 55
