Vertically align numbers with Larger Number on top:
| 7 | 8 | |
| − | 4 | 2 |
Subtract using place value:
| Tens | Ones | |
|---|---|---|
| 78 | 7 | 8 |
| 42 | 4 | 2 |
| Difference | 3 | 6 |
Column traversal from right to left
Ones column:
Ones column:
- 8 − 2 = 6
Tens column:
- 7 − 4 = 3
| 7 | 8 | |
| − | 4 | 2 |
| 3 | 6 |
Therefore, the Difference between 78 and 42 is 36
Check computation by comparing Larger Number and the Sum of Smaller Number and Difference:
| 4 | 2 | |
| 3 | 6 | |
| 7 | 8 |
Sum of Smaller Number and Difference = 78
Sum of Smaller Number and Difference = Larger Number (78 = 78) ✓
