Fun With Math

MULTIPLYING LARGE NUMBERS

65 * 65 = 4225

How do you do that in your head??

Simple!

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RULES:
1) 1st digit should be the same
2) 2nd digit should total 10

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STEPS:
1) Multiply the 1st SAME digit by the 1st SAME digit +1

x * (x + 1)

or

6 * (6 + 1) = 42

2) Multiply the 2nd digits together

ex. 5 * 5 = 25

3) Put the two values together

ex. 4225

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Try these examples:

a) 48 * 42 = ?
b) 79 * 71 = ? (notice: use 09)
c) 34 * 36 = ?

It also works with larger numbers:

a) 103 * 107 = ?
b) 125 * 125 = ?
c) 991 * 999 = ?