## 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 3's number by 35

1. Choose a repeating 3's number (333, etc.)

2. Multiply it by 35.
3. The product is:
- first two digits are 11: 11
- next repeating digits are 6's, two fewer than
repeating 3's in the original number
- the last two digits are 55

#### Example:

1. If the first number is 33333:
2. Multiply the number by 35.
3. The product is:
- first two digits are 11: 11
- next repeating digits are 6's, two fewer than
repeating 3's in the original number: 666
- the last two digits are 55: 55.
4. So 33333 × 35 = 1166655.

#### Example:

1. If the first number is 3333333333:
2. Multiply the number by 35.
3. The product is:
- first two digits are 11: 11
- next repeating digits are 6's, two fewer than
repeating 3's in the original number: 66666666
- the last two digits are 55: 55.
4. So 3333333333 × 35 = 116666666655.