## BEATCALC:  Beat the Calculator!

Back to Calculation Tips & Tricks

 From B. Lee Clay

Squaring Numbers

Multiplying Numbers

Dividing Numbers

Subtracting Numbers

Percents

Calculation
Practice Exercises

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### Subtract from a repeating 8's number, divide              by 9, subtract 10

1. Select a number between 2 and 9 digits made up of 8's.
2. Subtract a number equal to 9 minus the number of digits in the number you have selected.
3. Divide by 9. The answer will have one less digit than the original number in the series 98765432.
4. Subtract 10.

#### Example:

1. If the repeating number selected has 4 digits: 8888:
2. Subtract 5 (9 minus the number of digits) and divide by 9. The answer will be 987 (1 less digit in sequence than the 4 digits in the selected number).
3. Subtract 10: 987 - 10 = 977.
4. So (8888-5) / 9 - 10 = 977.

See the pattern?

1. If the repeating number selected has 6 digits: 888888:
2. Subtract 3 (9 minus the number of digits) and divide by 9. The answer will be 98765 (1 less digit in sequence than the 6 digits in the selected number).
3. Subtract 10: 98765 - 10 = 98755.
4. So (888888-3) / 9 - 10 = 98755.
Extend this exercise by changing the last number to subtract, producing a multitude of easily answered problems.