คำตอบ - Long subtraction
2.877
คำอธิบายทีละขั้นตอน
1. Rewrite the numbers from top to bottom, aligned by their place values
| Place value | ones | . | tenths | hundredths | thousandths |
| 8 | |||||
| - | 5 | . | 1 | 2 | 3 |
| . |
Put zeros in the blank number places:
| Place value | ones | . | tenths | hundredths | thousandths |
| 8 | . | 0 | 0 | 0 | |
| - | 5 | . | 1 | 2 | 3 |
| . |
2. Subtract the numbers using long subtraction method
Because the upper digit (0) in the thousandths column is too small to get a positive difference, borrow 1 from the number to the left (8.00) which becomes (7.99) and get (10).
| Place value | ones | . | tenths | hundredths | thousandths |
| 7 | 9 | 9 | 10 | ||
| 8 | . | 0 | 0 | 0 | |
| - | 5 | . | 1 | 2 | 3 |
| . |
Subtract the numbers in the thousandths column from the top number:
10-0-3=7
| Place value | ones | . | tenths | hundredths | thousandths |
| 7 | 9 | 9 | 10 | ||
| 8 | . | 0 | 0 | 0 | |
| - | 5 | . | 1 | 2 | 3 |
| . | 7 |
Subtract the numbers in the hundredths column from the top number:
9-2=7
| Place value | ones | . | tenths | hundredths | thousandths |
| 7 | 9 | 9 | 10 | ||
| 8 | . | 0 | 0 | 0 | |
| - | 5 | . | 1 | 2 | 3 |
| . | 7 | 7 |
Subtract the numbers in the tenths column from the top number:
9-1=8
| Place value | ones | . | tenths | hundredths | thousandths |
| 7 | 9 | 9 | 10 | ||
| 8 | . | 0 | 0 | 0 | |
| - | 5 | . | 1 | 2 | 3 |
| . | 8 | 7 | 7 |
Subtract the numbers in the ones column from the top number:
7-5=2
| Place value | ones | . | tenths | hundredths | thousandths |
| 7 | 9 | 9 | 10 | ||
| 8 | . | 0 | 0 | 0 | |
| - | 5 | . | 1 | 2 | 3 |
| 2 | . | 8 | 7 | 7 |
The solution is: 2.877
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