This innovative collection of shortcuts and proprietary techniques lets you perform complex calculations—multiplication, squares, division—with lightning speed. Solve problems in your head, effortlessly. Calculate smarter, faster!
here are some trick to make math easy:
Square near 100
99^2=(99-1)|1^2
=9801
102^2=100+2|2^2
=10204
Square near 50
Magic number 25
56^2=25+6|6^2
=3136
48^2=25-2|2^2
=2304
Square number with unit place 5
65^2=6*7|5^2
=4225
85^2=8*9|5^2
=7225
Multiplication with 11
28*11=2|(2+8)|8
=2+{1}|0|8
=308
Multiplication of 2 digit number with unit place sum 10
42*48=4*5|2*8
=2016
Multiflication with 101
12*101=12 | 12
=1212
Square root
Square root of 17(16+1) = 4+(1/2*8)
=4 + 1/8
=4+0.12
=4.12
Square of any 2 digit number
21^2=2^2|2*1*2|1^2
=441
Square of the three digit number with 10's place 0
305^2=3^2|3*5*2|5^2
=93025
1+2+3+......+n = n*(n+1)/2
Example : 1+2+3+............+100=100*(100+1)/2
=100*101/2
=50*101
=5050
Handshake Problem:
n*(n-1)/2 [formula]
Handshake among 40 student. n=40
40*(40-1)/2
=20*39
=780
multiplication of two digit number with unit place 1 :
31*21= 3*2|3+2|1*1
= 651
Addition of alternate number :
47+74=11*(4+7)
=11*11
=121
27+72=11*(2+7)
=11*9
=99
DIVISION BY 5
32/5=32*2/10
=64/10
=6.4
MULTIFLICATION BY 5
124*5=124/2*10
=62*10