คำตอบ - Long subtraction
39.8
คำอธิบายทีละขั้นตอน
1. Rewrite the numbers from top to bottom, aligned by their place values
| Place value | tens | ones | . | tenths |
| 5 | 0 | |||
| - | 1 | 0 | . | 2 |
| . |
Put zeros in the blank number places:
| Place value | tens | ones | . | tenths |
| 5 | 0 | . | 0 | |
| - | 1 | 0 | . | 2 |
| . |
2. Subtract the numbers using long subtraction method
Because the upper digit (0) in the tenths column is too small to get a positive difference, borrow 1 from the number to the left (50) which becomes (49) and get (10).
| Place value | tens | ones | . | tenths |
| 4 | 10 | |||
| 5 | 0 | . | 0 | |
| - | 1 | 0 | . | 2 |
| . |
Subtract the numbers in the tenths column from the top number:
10-0-2=8
| Place value | tens | ones | . | tenths |
| 4 | 10 | |||
| 5 | 0 | . | 0 | |
| - | 1 | 0 | . | 2 |
| . | 8 |
Subtract the numbers in the ones column from the top number:
9-0=9
| Place value | tens | ones | . | tenths |
| 4 | 10 | |||
| 5 | 0 | . | 0 | |
| - | 1 | 0 | . | 2 |
| 9 | . | 8 |
Subtract the numbers in the tens column from the top number:
4-1=3
| Place value | tens | ones | . | tenths |
| 4 | 10 | |||
| 5 | 0 | . | 0 | |
| - | 1 | 0 | . | 2 |
| 3 | 9 | . | 8 |
The solution is: 39.8
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