## BEATCALC:  Beat the Calculator!

Back to Calculation Tips & Tricks

 From B. Lee Clay

Squaring Numbers

Multiplying Numbers

Dividing Numbers

Subtracting Numbers

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Calculation
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### Multiplying a repeating 2's number by 77

1. Choose a repeating 2's number (222, etc.)
2. Multiply it by 77
3. The product is:
- the first two digits are 17
- the next digits are repeating 1's (three fewer than repeating 2's in the original number)
- the last three digits are 094

#### Example:

1. If the first number is 2222:
2. Multiply by 77.
3. The product is:
- the first two digits are 17.
- the next digits are repeating 1's (three fewer than repeating 2's in the original number): 1.
- the last three digits are 094.
4. So 2222 × 77 = 171094.

See the pattern?

1. If the first number is 222222:
2. The product is:
- the first two digits are 17.
- the next digits are repeating 1's (three fewer than repeating 2's in the original number): 111.
- the last three digits are 094.
3. So 222222 × 77 = 17111094.
Use the three steps above and you will be able to give these products quickly and accurately.