Multiplying a repeating 1's number by 55
Follow the following Steps:
- Choose a repeating 1's number (111, etc.)
- Multiply it by 55
- The product is:
- first digit is 6
- next digits are repeating 1's, two fewer than repeating 1's in the original number
- last two digits are 05.
- If the first number is 1111:
- Multiply by 55. The product is:
first digit is 6: 6
next digits are 1's - two fewer than 1's: 11
last two digits are 05 - So 1111 × 55 = 61105.
- If the first number is 111111:
- Multiply by 55. The product is:
first digit is 6: 6
next digits are 1's, two fewer than 1's: 1111
last two digits are 05 - So 111111 × 55 = 6111105.