## BEATCALC:  Beat the Calculator!

Back to Calculation Tips & Tricks

 From B. Lee Clay

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### Multiplying a repeating 6's number by 66

1. Choose a repeating 6's number (666, etc.)
2. Multiply it by 66
3. The product is:
- the first two digits are 43
- the next digits are repeating 9's (two fewer than repeating 6's in the original number)
- the last two digits are 56

#### Example:

1. If the first number is 6666:
2. Multiply by 66. The product is
- the first two digits are 43: 43.
- the next digits are repeating 9's (two fewer than repeating 6's in the original number): 9999.
- the last two digits are 56: 56.
3. So 66666 × 66 = 43999956.

See the pattern?

1. If the first number is 666666666:
2. Multiply by 66. The product is
- the first two digits are 43: 43.
- the next digits are repeating 9's (two fewer than repeating 6's in the original number): 9999999.
- the last two digits are 56: 56.
3. So 666666666 × 66 = 43999999956.
Follow the three steps and you will be serving up the products of these big six numbers by 66 with ease.