## BEATCALC:  Beat the Calculator!

Back to Calculation Tips & Tricks

 From B. Lee Clay

Squaring Numbers

Multiplying Numbers

Dividing Numbers

Subtracting Numbers

Finding Percents

Calculation
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### Multiplying a repeating 6's number by 16

1. Choose a repeating 6's number (6666, etc.)
2. Multiply it by 16
3. The product is:
- the first digits are 10
- the next digits are repeating 6's (two fewer than repeating 6's in the original number)
- the last digits are 56

#### Example:

1. If the first number is 666666:
2. Multiply by 16. The product is:
- the first digit is 10: 10.
- the next digits are repeating 6's (two fewer than repeating 6's in the original number): 6666.
- the last digits are 56.
3. So 16 × 666666 = 10666656.

See the pattern?

1. If the first number is 666666666:
2. Multiply by 16. The product is:
- the first digit is 10: 10.
- the next digits are repeating 6's (two fewer than repeating 6's in the original number): 6666666.
- the last digits are 56.
3. So 16 × 666666666 is 10666666656.