คำตอบ - Long subtraction
28.42
คำอธิบายทีละขั้นตอน
1. Rewrite the numbers from top to bottom, aligned by their place values
| Place value | tens | ones | . | tenths | hundredths |
| 5 | 5 | . | 8 | 1 | |
| - | 2 | 7 | . | 3 | 9 |
| . |
2. Subtract the numbers using long subtraction method
Because the upper digit (1) in the hundredths 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 (11).
| Place value | tens | ones | . | tenths | hundredths |
| 7 | 11 | ||||
| 5 | 5 | . | 8 | 1 | |
| - | 2 | 7 | . | 3 | 9 |
| . |
Subtract the numbers in the hundredths column from the top number:
11-9=2
| Place value | tens | ones | . | tenths | hundredths |
| 7 | 11 | ||||
| 5 | 5 | . | 8 | 1 | |
| - | 2 | 7 | . | 3 | 9 |
| . | 2 |
Subtract the numbers in the tenths column from the top number:
7-3=4
| Place value | tens | ones | . | tenths | hundredths |
| 7 | 11 | ||||
| 5 | 5 | . | 8 | 1 | |
| - | 2 | 7 | . | 3 | 9 |
| . | 4 | 2 |
Because the upper digit (5) in the ones column is too small to get a positive difference, borrow 1 from the digit (5) in the next number place which becomes (4) and get (15).
| Place value | tens | ones | . | tenths | hundredths |
| 4 | 15 | ||||
| 7 | 11 | ||||
| 5 | 5 | . | 8 | 1 | |
| - | 2 | 7 | . | 3 | 9 |
| . | 4 | 2 |
Subtract the numbers in the ones column from the top number:
15-7=8
| Place value | tens | ones | . | tenths | hundredths |
| 4 | 15 | ||||
| 7 | 11 | ||||
| 5 | 5 | . | 8 | 1 | |
| - | 2 | 7 | . | 3 | 9 |
| 8 | . | 4 | 2 |
Subtract the numbers in the tens column from the top number:
4-2=2
| Place value | tens | ones | . | tenths | hundredths |
| 4 | 15 | ||||
| 7 | 11 | ||||
| 5 | 5 | . | 8 | 1 | |
| - | 2 | 7 | . | 3 | 9 |
| 2 | 8 | . | 4 | 2 |
The solution is: 28.42
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