Multiplication Short Tricks
Multiplication of two numbers near but above 100
Suppose we want to multiply two numbers X and Y which are near and above 100.
Short trick : X ✕ Y = X + C2 | C1✕C2 Or Y + C1 | C1✕C2
where C1 = X-100 and C2 = Y-100
Example : Calculate 103 ✕ 104
X = 103 , Y = 104
C1 = 103-100 =3
C2 = 104 -100 =4
X ✕ Y = X + C2 | C1✕C2
= 103 + 4 | 3✕4
= 107|12 = 10712
Note : i) If C1 ✕ C2 come out to be a single digit , then add '0' before single digit.
ii) If C1 ✕ C2 come out to be a Three digit number , then carry forward extra digits to the left part of the solution.
Example : 111 * 112
Short trick : X ✕ Y = X + C2 + forward carry | C1✕C2 Or Y + C1 + forward carry | C1✕C2
C1✕C2 = 11 ✕ 12 = 132 , here 1 will be forwarded as carry left part
111 ✕ 112 = 111 + 12 + 1 | 32 = 124 | 32 = 12432
Multiplication of two numbers near but below 100
Suppose we want to multiply two numbers X and Y which are near and below 100
Short trick : X ✕ Y = X + C2 | C1✕C2 Or Y + C1 | C1✕C2
where C1 = X-100 and C2 = Y-100
Example : Calculate 96 ✕ 95
X = 96 , Y = 95
C1 = 96 - 100 = -4
C2 = 95 - 100 = -5
X ✕ Y = X + C2 | C1✕C2
= 96 -5 | 4✕5
= 91|20 = 9120
Note : i) If C1 * C2 come out to be a single digit , then add '0' before single digit.
Multiplication of any number with 99 , 999 , 9999
Short Trick : Multiple 59 ✕ 99
59 ✕ 99 = (59-1) | 100 - 59 = 58 | 41 = 5841
Squaring Short Tricks
Some Properties Of Perfect square :
1. Any Perfect Square always ends with 0 ,1 , 4 , 5 , 9 . If not , it can't be a perfect square.
2. If any number ends with odd number of zeros , it can never be perfect square.
3. If a number is divided by 3 , leaves a remainder 2 , it can never be a perfect square.
4. If a number can be expressed as the sum of successive odd natural number starting from 1 . thus , the number is a perfect square.
For example :4 = 1 + 3
9 = 1 + 3 + 5
16 = 1 + 3 + 5 + 7
25 = 1 + 3 + 5 + 7 + 9
Square of numbers with all digits 1
(111111....n times)2 = 123456.....n.....54321
112 = 121
1112 = 12321
11112= 1234321
111112 = 123454321
Square of numbers ends with 5
Short tricks : left*(left + 1) | 25
Example : Square of 75
Here the last digit is 5, left part is 7 :
The answer : 7*(7+1) | 25 = 7*8 | 25 = 5625
Squaring of number between 50 and 60
Short tricks : 52 + (Right Digit) | (Right Digit)2
Example : square of 54
52 + (Right Digit) | (Right Digit)
25 + 4 | 42
29|16
2916
Squaring Of number near and above 100
Short Tricks : A+D | D2
where A = number whose square is to be found , D = difference of A from 100
Example : Square of 103 :
A = 103 , D = 3
Square = 103+3 | 32 = 106 | 09
10609Cube Root Short Tricks
In this trick , We'll learn how to find the cube root of perfect cubes. In this video, we will discuss a short trick of finding the cube root trick of perfect cubes only.
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