คำตอบ - Long subtraction
21.05
คำอธิบายทีละขั้นตอน
1. Rewrite the numbers from top to bottom, aligned by their place values
| Place value | tens | ones | . | tenths | hundredths |
| 8 | 0 | . | 2 | 5 | |
| - | 5 | 9 | . | 2 | |
| . |
Put zeros in the blank number places:
| Place value | tens | ones | . | tenths | hundredths |
| 8 | 0 | . | 2 | 5 | |
| - | 5 | 9 | . | 2 | 0 |
| . |
2. Subtract the numbers using long subtraction method
Subtract the numbers in the hundredths column from the top number:
5-0=5
| Place value | tens | ones | . | tenths | hundredths |
| 8 | 0 | . | 2 | 5 | |
| - | 5 | 9 | . | 2 | 0 |
| . | 5 |
Subtract the numbers in the tenths column from the top number:
2-2=0
| Place value | tens | ones | . | tenths | hundredths |
| 8 | 0 | . | 2 | 5 | |
| - | 5 | 9 | . | 2 | 0 |
| . | 0 | 5 |
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 | hundredths |
| 7 | 10 | ||||
| 8 | 0 | . | 2 | 5 | |
| - | 5 | 9 | . | 2 | 0 |
| . | 0 | 5 |
Subtract the numbers in the ones column from the top number:
10-9=1
| Place value | tens | ones | . | tenths | hundredths |
| 7 | 10 | ||||
| 8 | 0 | . | 2 | 5 | |
| - | 5 | 9 | . | 2 | 0 |
| 1 | . | 0 | 5 |
Subtract the numbers in the tens column from the top number:
7-5=2
| Place value | tens | ones | . | tenths | hundredths |
| 7 | 10 | ||||
| 8 | 0 | . | 2 | 5 | |
| - | 5 | 9 | . | 2 | 0 |
| 2 | 1 | . | 0 | 5 |
The solution is: 21.05
ทำไมต้องเรียนสิ่งนี้
Learn more with Tiger
Why learn this