## 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 3's number by the same number of 9's

1. Choose a repeating 3's number (333, etc.)
2. Multiply it by the same number of 9's (999, etc.)
3. The product is:
One fewer 3 than there were digits in the original number.
One 2.
One fewer 6 than digits in original number.
One 7.

#### Example:

1. If the first number is 333:
2. Multiply by 999.
3. The product is:
One fewer 3 than digits in original number: 33
One 2: 332
One fewer 6 than digits in original number: 33266
One 7: 332667
4. So 333 × 999 is 332667.

See the pattern?

1. If the first number is 33333:
2. Multiply by 99999.
3. The product is:
One fewer 3 than digits in original number: 3333
One 2: 33332
One fewer 6 than digits in original number: 333326666
One 7: 3333266667
4. So 33333 × 99999 is 3333266667.