# Shortcuts to Perform Mathematical Operations

Friends, we have already discussed the following methods in our various posts which we have updated earlier. In this post we are just summarizing all those simple time saving techniques with examples so that it will be easier for you to have a quick review.

We can solve this problem in many ways.
• 37+30+8 = 75
• 37+3+35 = 75
• 37 + 40 - 2 = 75

### Subtraction Shortcuts :

Subtract 25 from 67
Since 25 = 20 + 5 ,
67-25 = 67 - 20 - 5 = 42

### Multiplication Shortcuts :

Multiply 12 and 50
12 x 50 = 12 x 5 x 10
= 60x10 = 600

(You can actually multiply by 5 and then add a zero to it)

Note : We all know that, to multiply a number by 10, 100 or 1000, we add zeroes at the end of the given number.

28x10 = 280
325x100 = 32500
4623 x 1000 = 4623000

So if you want to multiply 5 with any number, then just add a zero to it and divide it with 2.

28 x 5 = 280/2 = 140

Multiply 569 x 99
We can use the same method explained above to solve this problem

as 99 = 100-1

569 x 99 = 569 x (100-1)
= 569 x 100 - 569 x 1
= 56900 - 569 = 56331

To multiply by 25, as 25 = (100/4), it is enough if we multiply the number by 100 and then divide the same by 4.

Multiply 64 and 25
We will consider 25 as 100/4 to solve this problem.
64 x 25 = 64x(100/4)
= 16x100 = 1600

Multiply 64 and 50
To multiply by 50, as 50 = 100/2,
it is enough if we multiply the number with 100 and then divide by 2.
64 x 50 = 64x (100/2) = (64/2) x 100 = 32x100 = 3200
Therefore, 64 x 50 = 3200

Multiply 105 x 51
We can take 51 as 50+1
so, 105 x 51
= 105 x (50+1)
= 105 x 50 + 105 x 1

=  ((105 x 100)/2) + 105 = (10500/2_ + 105 = 5250 + 1058 = 5355

Therefore, 105 x 51 = 5355

Multiply 64 x 125
To multiply a number by 125, as 125 = 1000/8, we can multiply the number by 1000 and then divide by 8.

64 x 125 = 64 x 1000/8
= 64/8 x 1000 = 8x1000 = 8000

Therefore, 64x125 = 8000

Multiply 648 x 127
We can take 127 as 125+2
648x127 = 648x(125+2)
= 648x125 + 648x2
= 648 x (1000/8) + 648x2
= 8100 x 1296
= 82296

now let us move on to the problems of divisions.

### Division Shortcuts :

Note : While performing division, sometimes, the divisor can be converted into a fraction of 10, 100 or 1000. But you must remember to change the numerator accordingly in order to keep the value unchanged.

Divide 1500 % 500

1500/500 = (1500x2) / (500x2)
= 3000/1000 = 3

Simplify 350%50
350/50 = (350x2) / (50x2)  = 700/100 = 7
Divide 420 % 20
= 420/20 = (420x5)/(20/5)
= 2100/100 = 21

That's all for now friends. You can check detailed shortcut techniques of math from here. Happy Reading.

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1. thank you very much ..

2. multiply by 5 = multiply by 10 / divide by 2
multiply by 25 = multiply by 100 / divide by 4

3. 569*99 simple trick when multiplying by 99,88,66 etc.

569*9 unit place 9*9=8(1) carry 8 then 6+9=15*9 =135+8=14(3) carry 14 then 5+6=11*9=99+14=11(3) carry 11 then 5*9=45+11=(56)
thank you

1. Thank u very much ...... It is so useful for bank exams.
plz send me other mental technics.
my email: jitendrahmr@gmail.com,,,
plz as soon as possible

4. Onther one tric for sqaure 40 to 60
firt squre of 50 = 2500 take as a prefrence now

you want 42 sqaure

50-42= 8
now 2500
- 8
_______
17
now ad in 8 squre 64
if above then 50 to do not minas but ad
54 squre 25+4 =29
2916

1. xclnt dr....Hatz off....

2. thanq very much...

5. Onther one tric for sqaure 40 to 60
firt squre of 50 = 2500 take as a prefrence now

you want 42 sqaure

50-42= 8
now 2500
- 8
_______
17
now ad in 8 squre 64
if above then 50 to do not minas but ad
54 squre 25+4 =29
2916

6. We can remember easily 41 to 50 squares..
Jst write 16 to 25 frm top to bottom nd again write squares of 0 to 9 from bottom to top.. Hope u al understd
41=1681
42=1764
43=1849
44=1936
45=2025
46=2116
47=2209
48=2304
49=2401
50=2500

1. thanq...its a simple technique...

7. (42)2
First do square of 2 = 4
Den 4*2*2 = 16 so carry 1
Den square of 4 = 16 + 1- carry = 17
:1764
Its nothing but a²+2ab+b²

Square of 86=
a²=64 so 64
2ab = 2*8*6=96 96
b² = 36 36
So 7396