คำตอบ - Long subtraction
คำอธิบายทีละขั้นตอน
1. Rewrite the numbers from top to bottom, aligned by their place values
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 7 | 7 | . | 2 | |||
| - | 4 | 3 | . | 7 | 7 | 8 |
| . |
Put zeros in the blank number places:
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 7 | 7 | . | 2 | 0 | 0 | |
| - | 4 | 3 | . | 7 | 7 | 8 |
| . |
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 (20) which becomes (19) and get (10).
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 1 | 9 | 10 | ||||
| 7 | 7 | . | 2 | 0 | 0 | |
| - | 4 | 3 | . | 7 | 7 | 8 |
| . |
Subtract the numbers in the thousandths column from the top number:
10-0-8=2
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 1 | 9 | 10 | ||||
| 7 | 7 | . | 2 | 0 | 0 | |
| - | 4 | 3 | . | 7 | 7 | 8 |
| . | 2 |
Subtract the numbers in the hundredths column from the top number:
9-7=2
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 1 | 9 | 10 | ||||
| 7 | 7 | . | 2 | 0 | 0 | |
| - | 4 | 3 | . | 7 | 7 | 8 |
| . | 2 | 2 |
Because the upper digit (1) in the tenths column is too small to get a positive difference, borrow 1 from the digit (7) in the next number place which becomes (6) and get (11).
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 6 | 11 | |||||
| 1 | 9 | 10 | ||||
| 7 | 7 | . | 2 | 0 | 0 | |
| - | 4 | 3 | . | 7 | 7 | 8 |
| . | 2 | 2 |
Subtract the numbers in the tenths column from the top number:
11-7=4
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 6 | 11 | |||||
| 1 | 9 | 10 | ||||
| 7 | 7 | . | 2 | 0 | 0 | |
| - | 4 | 3 | . | 7 | 7 | 8 |
| . | 4 | 2 | 2 |
Subtract the numbers in the ones column from the top number:
6-3=3
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 6 | 11 | |||||
| 1 | 9 | 10 | ||||
| 7 | 7 | . | 2 | 0 | 0 | |
| - | 4 | 3 | . | 7 | 7 | 8 |
| 3 | . | 4 | 2 | 2 |
Subtract the numbers in the tens column from the top number:
7-4=3
| Place value | tens | ones | . | tenths | hundredths | thousandths |
| 6 | 11 | |||||
| 1 | 9 | 10 | ||||
| 7 | 7 | . | 2 | 0 | 0 | |
| - | 4 | 3 | . | 7 | 7 | 8 |
| 3 | 3 | . | 4 | 2 | 2 |
The solution is: 33.422
ทำไมต้องเรียนสิ่งนี้
Learn more with Tiger
Why learn this