Soluzione - Long subtraction
Spiegazione passo passo
1. Rewrite the numbers from top to bottom, aligned by their place values
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
2. Subtract the numbers using long subtraction method
Because the upper digit (2) in the ones column is too small to get a positive difference, borrow 1 from the digit (1) in the next number place which becomes (0) and get (12).
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
Subtract the numbers in the ones column from the top number:
12-3=9
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 9 |
Because the upper digit (0) in the tens column is too small to get a positive difference, borrow 1 from the number to the left (10) which becomes (09) and get (10).
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 9 |
Subtract the numbers in the tens column from the top number:
10-1=9
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 9 | 9 |
Subtract the numbers in the hundreds column from the top number:
9-0=9
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 9 | 9 | 9 |
Because the upper digit (0) in the thousands 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 (10).
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 1 | 10 | ||||||
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 9 | 9 | 9 |
Subtract the numbers in the thousands column from the top number:
10-1=9
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 1 | 10 | ||||||
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 9 | 9 | 9 | 9 |
Because the upper digit (1) in the ten thousands column is too small to get a positive difference, borrow 1 from the number to the left (80) which becomes (79) and get (11).
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 7 | 9 | 11 | |||||
| 1 | 10 | ||||||
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 9 | 9 | 9 | 9 |
Subtract the numbers in the ten thousands column from the top number:
11-2=9
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 7 | 9 | 11 | |||||
| 1 | 10 | ||||||
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 9 | 9 | 9 | 9 | 9 |
Subtract the numbers in the hundred thousands column from the top number:
9-5=4
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 7 | 9 | 11 | |||||
| 1 | 10 | ||||||
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 4 | 9 | 9 | 9 | 9 | 9 |
Write 7 in the millions place.
| Place value | millions | hundred thousands | ten thousands | thousands | hundreds | tens | ones |
| 7 | 9 | 11 | |||||
| 1 | 10 | ||||||
| 0 | 9 | 10 | |||||
| 0 | 12 | ||||||
| 8 | 0 | 2 | 1 | 0 | 1 | 2 | |
| - | 5 | 2 | 1 | 0 | 1 | 3 | |
| 7 | 4 | 9 | 9 | 9 | 9 | 9 |
The solution is: 7,499,999
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