คำตอบ - Long subtraction
0.3
คำอธิบายทีละขั้นตอน
1. Rewrite the numbers from top to bottom, aligned by their place values
| Place value | ones | . | tenths | hundredths |
| 2 | . | 1 | 5 | |
| - | 1 | . | 8 | 5 |
| . |
2. Subtract the numbers using long subtraction method
Subtract the numbers in the hundredths column from the top number:
5-5=0
| Place value | ones | . | tenths | hundredths |
| 2 | . | 1 | 5 | |
| - | 1 | . | 8 | 5 |
| . | 0 |
Because the upper digit (1) in the tenths column is too small to get a positive difference, borrow 1 from the digit (2) in the next number place which becomes (1) and get (11).
| Place value | ones | . | tenths | hundredths |
| 1 | 11 | |||
| 2 | . | 1 | 5 | |
| - | 1 | . | 8 | 5 |
| . | 0 |
Subtract the numbers in the tenths column from the top number:
11-8=3
| Place value | ones | . | tenths | hundredths |
| 1 | 11 | |||
| 2 | . | 1 | 5 | |
| - | 1 | . | 8 | 5 |
| . | 3 | 0 |
Subtract the numbers in the ones column from the top number:
1-1=0
| Place value | ones | . | tenths | hundredths |
| 1 | 11 | |||
| 2 | . | 1 | 5 | |
| - | 1 | . | 8 | 5 |
| 0 | . | 3 | 0 |
The solution is: 0.3
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