Solution - Long multiplication
Step-by-step explanation
1. Rewrite the numbers from top to bottom aligned to the right
| Place value | thousands | hundreds | tens | ones |
| 8 | 1 | |||
| × | 2 | 1 | ||
2. Multiply the numbers using long multiplication method
Start by multiplying the ones digit (1) of the multiplier 21 by each digit of the multiplicand 81, from right to left.
Multiply the ones digit (1) of the multiplicator by the number in the ones place value:
1×1=1
Write 1 in the ones place.
| Place value | thousands | hundreds | tens | ones |
| 8 | 1 | |||
| × | 2 | 1 | ||
| 1 | ||||
Multiply the ones digit (1) of the multiplicator by the number in the tens place value:
1×8=8
Write 8 in the tens place.
| Place value | thousands | hundreds | tens | ones |
| 8 | 1 | |||
| × | 2 | 1 | ||
| 8 | 1 | |||
81 is the first partial product.
Proceed by multiplying the tens digit (2) of the multiplier (21) by each digit of the multiplicand (81), from right to left.
Because digit (2) is in tens place, we shift partial result by 1 place(s) by placing 1 zero(s).
| Place value | thousands | hundreds | tens | ones |
| 8 | 1 | |||
| × | 2 | 1 | ||
| 8 | 1 | |||
| 0 |
Multiply the tens digit (2) of the multiplicator by the number in the ones place value:
2×1=2
Write 2 in the tens place.
| Place value | thousands | hundreds | tens | ones |
| 8 | 1 | |||
| × | 2 | 1 | ||
| 8 | 1 | |||
| 2 | 0 |
Multiply the tens digit (2) of the multiplicator by the number in the tens place value:
2×8=16
Write 6 in the hundreds place.
Because the result is greater than 9, carry the 1 to the thousands place.
| Place value | thousands | hundreds | tens | ones |
| 1 | ||||
| 8 | 1 | |||
| × | 2 | 1 | ||
| 8 | 1 | |||
| 1 | 6 | 2 | 0 |
1,620 is the second partial product.
3. Add the partial products
81+1620=1701 long addition steps can be seen here
| Place value | thousands | hundreds | tens | ones |
| 8 | 1 | |||
| × | 2 | 1 | ||
| 8 | 1 | |||
| + | 1 | 6 | 2 | 0 |
| 1 | 7 | 0 | 1 |
The solution is: 1,701
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