## 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 12

1. Choose a repeating 6's number (6666, etc.)
2. Multiply it by 12
3. The product is:
- the first digit is 7
- the next digits are repeating 9's (one fewer than repeating 6's in the original number)
- the last digit is 2

#### Example:

1. If the first number is 6666:
2. Multiply by 12. The product is:
- the first digit is 7: 7.
- the next digits are repeating 9's (one fewer than repeating 6's in the original number): 999.
- the last digit is 2: 2.
3. So 12 × 6666 = 79992.

See the pattern?

1. If the first number is 66666666:
2. Multiply by 12. The product is:
- the first digit is 7: 7.
- the next digits are repeating 9's (one fewer than repeating 6's in the original number): 9999999.
- the last digit is 2: 2.
3. So 12 × 66666666 = 799999992.
The three steps will enable you to give these answers quickly and easily.