**Banking Exam Preparation – “MULTIPLICATION” Part I**

**Remember some important formula – **

- (a + b)
^{2}= a^{2}+ 2ab + b^{2} - (a + b)
^{2 }= (a – b)^{2}+ 4ab - (a – b)
^{2 }= a^{2}– 2ab + b^{2} - (a – b)
^{2 }= (a + b)^{2 }– 4ab - a
^{2}–b^{2}= (a – b)(a + b) - (a + b)
^{3}= a^{3}+ b^{3}+ 3ab(a + b) = a^{3}+ b^{3}+ 3a^{2}b + 3ab^{2} - (a – b)
^{3}= a^{3}– b^{3}– 3ab(a – b) = a^{3}– b^{3}– 3a^{2}b + 3ab^{2} - a
^{3}+ b^{3 }= (a + b)^{3}– 3ab(a + b) - a
^{3}+ b^{3 }= (a + b)( a^{2}– ab + b^{2}) - a
^{3}– b^{3}= (a – b)^{3}+ 3ab(a – b) - a
^{3}– b^{3}= (a – b)(a^{2}+ ab + b^{2}) - a
^{m}x a^{n}= a^{m+n} - a
^{m}/ a^{n}= a^{m – n } - (a/b)
^{(m/n)}=(b/a)^{-(m/n)} - a
^{m}/ b^{-n}= a^{m}x b^{n}

**Banking Exam Preparation – “MULTIPLICATION” Part I**

** **

Multiply any two digit numbers

**AB x CD = 100(A x C) + 10{(A x D) + (B x C)} + B x D**

E.g. 43 x 58 = ?

43 x 58 = 100(4 x 5) + 10{(4 x 8) + (3 x 5)} + 3 x 8

= 100 x 20 + 10{32 + 15) +24

= 2000 + 10{47} + 24

= 2000 + 470 + 24

= 2470 + 24

= **2494**

**You can get answer in less than 8 seconds by practice more and more.**

**Banking Exam Preparation – “MULTIPLICATION” Part I**

** **

Two numbers that differ by 1

E.g. 45 x 44 = ?

** Square larger number and less large number**

45^{2} = 2025

2025 – 45 = 1980

E.g. 45 x 46 = ?

** Square smaller number and add smaller number**

45^{2} = 2025

2025 + 45 = 2070

** **

**Banking Exam Preparation – “MULTIPLICATION” Part I**

** **

Two numbers that differ by 2- **{(a + b)/2} ^{2} – 1**

E.g. 27 x 29 = ?

27 + 29 = 56

56/2 =28

28^{2} = (30 – 2)^{2} = 30^{2} – 2 x 30 x 2 + 2^{2 }= 900 – 120 + 4 = 784

784 – 1 = **783**

**You can get answer in less than 15 seconds by practice more and more.**

**Banking Exam Preparation – “MULTIPLICATION” Part I**

Two numbers that differ by 3- **(Smaller number + 1) ^{2} + (Smaller number – 1)**

E.g. 26 x 29 = ?

(26 + 1)^{2} + (26 – 1)

27^{2} + 25

729 +25 = **754**

Two numbers that differ by 4- **{(a + b)/2} ^{2} – 4**

E.g. 62 x 66 = ?

62 + 66 = 128

128/2 = 64

64^{2} = (65 – 1)^{2} = 65^{2} – 2 x 65 x 1 + 1^{2} = 4225 – 130 + 1 = 4096

4096 – 4 = **4092**

Two numbers that differ by 6- **{(a + b)/2} ^{2} – 9**

E.g. 42 x 48 = ?

42 + 48 = 90

90/2 = 45

45^{2} = 2025

2025 – 9 = **2016**

Two numbers that differ by an Even number where a < b and C = (b – a)/2

**{(a + b)/2} ^{2} – c^{2} **

E.g. 51 x 59 = ?

51 + 59 = 110

110/2 = 55

55^{2} = 3025

59 – 51 = 8

8/2 = 4

4^{2} = 16

3025 – 16 = **3009**

Two numbers that differ by an Odd number where a < b and C = [1 + (b – a)]/2

**(a + c) ^{2} – [b + (c – 1)^{2}] **

E.g. 51 x 58 = ?

C = 58 – 51 + 1/ 2 = 8/2 = 4

51 + 4 = 55

55^{2 }= 3025

58 + 3^{2} = 67

3025 – 67 = **2958**

**Banking Exam Preparation – “MULTIPLICATION” Part I**

You can also find

Banking Exam Preparation – “Square and Square Root”

BANKING EXAM PREPARATION – CUBE AND CUBE ROOT

Banking Exam Preparation – ADDITION and SUBTRACTION Part I

Banking Exam Preparation – ADDITION and SUBTRACTION Part II

Banking Exam Preparation – ADDITION and SUBTRACTION Part III

Banking **Exam Preparation – “MULTIPLICATION” Part I**

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