## 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 9's number by 27

1. Choose a repeating 9's number (e.g., 9999).
2. The product is made up of:
- first two digits are 26.
- next digits are repeating 9's -- two fewer than repeating 9's in original number.
- last two digits are 73.

#### Example:

1. The repeating 9's number chosen to multiply by 27 is 999999.
2. First two digits are 26: 26.
3. Next digits are repeating 9's -- two fewer than repeating 9's in original number: 9999.
4. Last two digits are 73: 73.
5. So 27 × 999999 is 26999973.

See the pattern?

1. The repeating 9's number chosen to multiply by 27 is 9999999999.
2. First two digits are 26: 26.
3. Next digits are repeating 9's -- two fewer than repeating 9's in original number: 99999999.
4. Last two digits are 73: 73.
5. So 27 × 9999999999 is 269999999973.
Use these three steps and you will be able to give these products at the amazement of your friends.