## BEATCALC:  Beat the Calculator!

Back to Calculation Tips & Tricks

 From B. Lee Clay

Squaring Numbers

Multiplying Numbers

Dividing Numbers

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### Multiplying a repeating 6's number by 31

1. Choose a repeating 6's number (666, etc.)
2. Multiply it by 31
3. The product is:
- the first two digits are 20
- the next digits are repeating 6's (two fewer than repeating 6's in the original number)
- the last two digits are 46

#### Example:

1. If the first number is 66666:
2. Multiply by 31. The product is:
- the first two digits are 20: 20.
- the next digits are repeating 6's (two fewer than repeating 6's in the original number): 666.
- the last two digits are 46: 46.
3. So 66666 × 31 = 2066646.

See the pattern?

1. If the first number is 66666666:
2. Multiply by 31. The product is:
- the first two digits are 20: 20.
- the next digits are repeating 6's (two fewer than repeating 6's in the original number): 666666.
- the last two digits are 46: 46.
3. So 66666666 × 31 = 2066666646.
Use these three steps and you will be giving these products easily and correctly.