## BEATCALC:  Beat the Calculator!

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 From B. Lee Clay

Squaring Numbers

Multiplying Numbers

Dividing Numbers

Subtracting Numbers

Finding Percents

Calculation
Practice Exercises

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### Multiplying a 2-, 3-, 4-, or 5-digit number                 by 100001

1. The product of a 2-digit number and 100,001 is:

first the two digits,
then three zeros,
then the two digits again.

Examples:

12 × 100001 = 1200012
79 × 100001 = 7900079

2. The product of a 3-digit number and 100,001 is:

first the three digits,
then two zeros,
then the three digits again.

Examples:

386 × 100001 = 38600386
914 × 100001 = 91400914

3. The product of a 4-digit number and 100,001 is:

first the four digits,
then one zero,
then the four digits again.

Examples:

6295 × 100001 = 629506295
8106 × 100001 = 810608106

4. The product of a 5-digit number and 100,001 is:

first the five digits,
then the five digits again.

Examples:

12345X100001 = 1234512345
98765X100001 = 9876598765

Your friends will need a BIG calculator to keep up with you when you announce these products!