## 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 4's number by 22

• Choose a repeating 4's number (444, etc.)
• Multiply it by 22
• The product is:
- first digit is 9
- next digits are 7's - two fewer than the repeating 4's in the original number
- last two digits are 68.

#### Example:

1. If the first number is 4444:
2. Multiply by 22. The product is:
first digit is 9: 9
next repeating digits are 7's, two fewer than the repeating 4's in the original number: 77
last two digits are 68: 68
3. So 4444 × 22 = 97768.

See the pattern?

1. If the first number is 4444444:
2. Multiply by 22. The product is:
first digit is 9: 9
next repeating digits are 7's, two fewer than the repeating 4's in the original number: 77777
last two digits are 68: 68
3. So 4444444 × 22 = 97777768.
Remember the pattern and you will be able to give these products with ease.

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10 January 2005
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