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Number Tricks

Numbers Reversed

2178 * 4 = 8712
1089 * 9 = 9801
123456789 * 8 + 9 = 987654321
987654312/8 = 123456789
1634482758620689655172413793 * 3 = 3163448275862068965517241379

All Alike

12345679 * 9 = 111111111
12345679 * 18 = 222222222
12345679 * 27 = 333333333
12345679 * 36 = 444444444
12345679 * 45 = 555555555
12345679 * 54 = 666666666
12345679 * 63 = 777777777
12345679 * 72 = 888888888
12345679 * 81 = 999999999

Ones

1 * 9 + 2 = 11
12 * 9 + 3 = 111
123 * 9 + 4 = 1111
1234 * 9 + 5 = 11111
12345 * 9 + 6 = 111111
123456 * 9 + 7 = 1111111
1234567 * 9 + 8 = 11111111
12345678 * 9 + 9 = 111111111
12345679 * 9 = 111111111
123456789 * 9 + 10 = 1111111111

12=1
112=121
1112=12321
11112=1234321
111112=123454321
1111112=12345654321
11111112=1234567654321
111111112=123456787654321
1111111112=12345678987654321

Trickery

n * 2 + 4 * 5 + 12 * 10 - 320 = 100n

YourBdayMonth * 2 + 5 * 50 + YourAge - 365 + 115 = Your Month in 100's, Your Age in 00's

A number in the form of abcabc is a multiple of 7, 11, and 13, or 1001!

Every odd number greater than seven is the sum of three prime numbers.

The expression n2 - n + 41 generates prime numbers foir all values of n from 1 to 40.

Divisible By...

A number is divisible by 2 if the last digit is even.

A number is divisible by 3 if the sum of its digits is divisible by 3.

A number is divisible by 4 if the last two digits are divisible by 4.

A number is divisible by 5 if the last digit is either "5" or "0".

A number is divisible by 6 if the sum of its digits is divisible by 3 AND the last digit is even.

A number is divisible by 8 if the last three digits are divisible by 8.

A number is divisible by 9 if the sum of its digits are divisible by 9.

Einstein's Theorem

E = mc2 is the conversion of matter into energy.

E = energy in ergs
m = mass of the matter in grams
c = speed of light in centimeters per second, c2=9 x 1020

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