math tricks for number theory
Post on 28-Nov-2014
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DESCRIPTION
It is about The uniqueness of number 9.
TRANSCRIPT
Math Tricks for Number Theory
Finda Dwi Permatahati (110210101011)
Dini Mustika Sari (110210101013)
Fajri Maulana (110210101014)
Multiplication by 25
24 x 25 =
?: 4 = 6 x 100 = 600
Multiplication by 25
24 x 25 =
: 4 = 6 x 100
24 x 25 =
2425
x 120
+600
= 60048
?
Multiplication by 25
123 x 25 =
? : 4 = 30 x 100
= 3000Remain = 3 x 25
Result =3075= 75
Exercises
4545 x 25 = ?278 x 25 =
?
12
The Uniqueness of Number
92468a7a =
?Can be divided by 9
The Uniqueness of Number
2468a7
2+4+6+8+a+7= 9k
Integer number a+27=
9k a = 0 or a = 9
9
Proof
246807 : 9 = 27423246897 : 9 = 27433
There’s no remain
Exercise
4545450009321
4895p2
12
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