**Banking Exam Preparation – ADDITION and SUBTRACTION- Part II**

**Continue from Banking Exam Preparation – ADDITION and SUBTRACTION- Part I**

**Counting Series (Natural Numbers):-**

E.g. 1,2,3,4,5,6,7 means start from 1 and useful for counting.

We can also apply Group addition method or we can apply formula

Formula – **n(n+1)/2**

Or Sum of odd numbers of series + sum of even numbers of series

Where n = number of elements in series

For e.g. 7(7+1)/2

7×8/2

56/2

28

Our answer is **28**

**Banking Exam Preparation – ADDITION and SUBTRACTION- Part II**

**Sum of all Odd numbers starting from 1.**

** **

E.g. Sum of the all odd number between 1 to 100.

Formula – **n ^{2}**

Where n = number of elements in series

For e.g. number of elements in series are 50

Then sum of the all odd number between 1 to 100 is 50^{2} = 2500

Our answer is **2500.**

** **

**Banking Exam Preparation – ADDITION and SUBTRACTION- Part II**

**Sum of all Even numbers starting from 1.**

** **

E.g. Sum of the all odd number between 1 to 100.

** **

**Formula – ** **n(n+1)**

Where n = number of elements in series.

For e.g. Number of elements in series are 50

Then Sum of the all odd number between 1 to 100.

50(50+1) = 50×51= **2550**

**Banking Exam Preparation – ADDITION and SUBTRACTION- Part II**

**Sum of squares of first ‘n’ natural numbers**

E.g. 1^{2} + 2^{2} + 3^{2} + 4^{2} + 5^{2}

Formula – **{n(n + 1)(2n + 1)}/6**

For e.g. 1^{2} + 2^{2} + 3^{2} + 4^{2} + 5^{2}

n = 5

= 5(5 + 1)(2×5 +1)/6

= 5x6x11/6

= 55

Our answer is **55**.

**Banking Exam Preparation – ADDITION and SUBTRACTION- Part II**

**Sum of cubes of first ‘n’ natural numbers**

E.g. 1^{3} + 2^{3} + 3^{3} + 4^{3} + 5^{3}

Formula – **{n (n + 1)/2} ^{2}**

For e.g. 1^{3} + 2^{3} + 3^{3} + 4^{3} + 5^{3}

n = 5

= {5 (5 + 1)/2}^{2}

= {5 x 6/2}^{2}

= 225

Our answer is **225.**

**Banking Exam Preparation – ADDITION and SUBTRACTION- Part II**

**SUBTRACTION:-**

**Left to right method-**

Calculate subtraction from left to right.

E.g. 1527 – 798

Then 1500 – 700 = 800

Now we need to less 98 then less 100 and add 2

Then 800 – 100 + 2 = 702

Now add 27

Then 702 + 27 = 729

Our answer is **729.**

** **

**Think that what number added to smaller to equals the larger**

Calculate from left to right

E.g. 884 – 340

Then 800 – 300 = 500

If we add 44 in 30 so we get 84.

Then our answer is 500 + 44 = **544**

** **

**Add a number to larger to round to next highest ‘0’ and then add same number to smaller and subtract**

Calculate from left to right

E.g. 595 – 278

Then 595 + 5 = 600 and 278 + 5 = 283

Then 600 – 283 = 317

Then our answer is **317**

**Add a number to smaller to round to next highest ‘10’, ‘100’ etc and then add same number to larger and subtract**

Calculate from left to right

E.g. 831 – 678

Then 678 + 22 = 700 and 831 + 22 = 853

Then 853 – 700 = 153

Then our answer is **153**.

**Banking Exam Preparation – ADDITION and SUBTRACTION- Part II**

**Continue to Banking Exam Preparation – ADDITION and SUBTRACTION- Part III**

You can also find

BANKING EXAM PREPARATION – CUBE AND CUBE ROOT

Banking Exam Preparation – ADDITION and SUBTRACTION- Part I

Banking Exam Preparation – ADDITION and SUBTRACTION- Part III

Banking Exam Preparation – “Square and Square Root”

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