คำตอบ - Long subtraction
53.1
คำอธิบายทีละขั้นตอน
1. Rewrite the numbers from top to bottom, aligned by their place values
| Place value | tens | ones | . | tenths |
| 8 | 1 | |||
| - | 2 | 7 | . | 9 |
| . |
Put zeros in the blank number places:
| Place value | tens | ones | . | tenths |
| 8 | 1 | . | 0 | |
| - | 2 | 7 | . | 9 |
| . |
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 digit (1) in the next number place which becomes (0) and get (10).
| Place value | tens | ones | . | tenths |
| 0 | 10 | |||
| 8 | 1 | . | 0 | |
| - | 2 | 7 | . | 9 |
| . |
Subtract the numbers in the tenths column from the top number:
10-0-9=1
| Place value | tens | ones | . | tenths |
| 0 | 10 | |||
| 8 | 1 | . | 0 | |
| - | 2 | 7 | . | 9 |
| . | 1 |
Because the upper digit (0) in the ones column is too small to get a positive difference, borrow 1 from the digit (8) in the next number place which becomes (7) and get (10).
| Place value | tens | ones | . | tenths |
| 7 | 10 | |||
| 0 | 10 | |||
| 8 | 1 | . | 0 | |
| - | 2 | 7 | . | 9 |
| . | 1 |
Subtract the numbers in the ones column from the top number:
10-7=3
| Place value | tens | ones | . | tenths |
| 7 | 10 | |||
| 0 | 10 | |||
| 8 | 1 | . | 0 | |
| - | 2 | 7 | . | 9 |
| 3 | . | 1 |
Subtract the numbers in the tens column from the top number:
7-2=5
| Place value | tens | ones | . | tenths |
| 7 | 10 | |||
| 0 | 10 | |||
| 8 | 1 | . | 0 | |
| - | 2 | 7 | . | 9 |
| 5 | 3 | . | 1 |
The solution is: 53.1
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