## 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 77

1. Choose a repeating 3's number (333, etc.)
2. Multiply it by 77
3. The product is:
- the first two digits are 25
- the next digits are repeating 6's (two fewer than repeating 3's in the original number)
- the last two digits are 41

#### Example:

1. If the first number is 3333:
2. First two digits are 25.
3. Next digits are repeating 6's -- two fewer than repeating 3's in the original number: 66.
4. Last two digits are 41.
5. So 77 × 3333 = 256641.

See the pattern?

1. Next pick is 333333:
2. First two digits are 25.
3. Next digits are repeating 6's -- two fewer than repeating 3's in the original number: 9999.
4. Last two digits are 41.
5. So 77 × 333333 = 25666641.

In no time you will be using this pattern to produce these huge products. And quickly, too.