Multiplying by 11
Use the following steps to multiply by 11:
- Write down the last digit of the number you are
multiplying by 11.
- Add the last digit to the digit on its left. Write down
the last digit of the sum and carry if necessary.
- Move one digit to the left.
- Add that digit to the digit on its left. Write (to the
left) and carry.
- Continue the process of moving to the left and adding
until there are no more digits.
Example:
23 × 11 =
| Write the last digit: 3 |
3 |
| Add 3 and 2. 3 + 2 = 5 |
53 |
| Move to the 2. |
|
| Since there are no more numbers to the
left of the 2 and there is no carry from the previous
sum, write down 2. |
253 |
Therefore, 23 × 11 = 253.
Example:
846 × 11 =
| Write the last number: 6 |
6 |
|
| Add 6 and 4. 6 + 4 = 10. |
06 |
(carry 1) |
| Move to the 4. |
|
|
| Add 4 and 8 and the carry. 4 + 8 + 1 = 13 |
306 |
(carry 1) |
| Move to the 8. |
|
|
| Since 8 is the last number, just add the
carry. 8 + 1 = 9 |
9306 |
|
Therefore, 846 × 11 = 9306.
|
