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Addition Tricks for Bank Exams – SBI Clerks and PO’s 2017

Addition Tricks for Bank Exams – SBI Clerks and PO’s 2017



To crack SBI clerk’s exam we need to be smart in doing calculations faster and accurate. So we have to use some maths tricks while solving aptitude section that traditional method of solving. Here we are providing some simple addition tricks with examples which are very much useful to crack upcoming SBI exams 2016.

Some Tricky Additions – Simplifications

IF you came across these type of additions we can follow this easy trick to solve in less time.

Model 1:

 1)     6 + 66 + 666+ 6666+ 66666+ 666666
= 6 × (123456)  ->  [Explanation: In above problem the number 6 repeated orderly 1 time, 2 times  …up to 6 times).] = 740736.

2)    4 + 44 + 444 + 4444 + 44444 + 444444
= 4 × (123456)
= 493824.

3) 7 + 77 + 777 + 7777 + 77777
= 7 × (1 2 3 4 5)
= 86415

Model 2:
1)  6.6 + 66.66 + 666.666 + 6666.6666 + 66666.66666
= 6 × (12345)   +  [6 × (54321)]->  [Explanation: In above problem the number 6 repeated orderly 1 time, 2 times  …up to 6 times).] = 74070 + 3.25926 ( 5 numbers after decimal point)
= 74073.25926

2) 4.4 + 44.44 + 444.444 + 4444.4444
= [4× ( 1 2 3 4)] + [ 4×(4 3 2 1)]

 = 4936  + 1.7284 ( 4 times repeatations after decimal point so keep decimal point upto 4 digits )

= 4937.7284.

Model 3:

1)  9.4 + 99.44 + 999.444 + 9999.4444

Step 1:
Before decimal point 9  repeated up to 4 times orderly from 1 time, 2 times …4 times. so multiply 9 with 1234.
[9 ×( 1234) ]  =  11106
Step 2:
After decimal point 4 repeated up to 4 times orderly from 1 to 4 numbers. So multiply 4 with (4321) and put the decimal point after 4 digits by counting from right to left.
[4 × (4321) ] = 1. 7284
Step 3:
Add step 1 + step2
11106  + 1.7284 = 11107.7284
Model 4:
What is the sum of all even natural numbers below 100
Solution:
2 + 4+ 6 + 8 + 10 +……+98
Formula: Sum =n/2 (f + l)      [n = total numbers, f = first number, l= last number].
= 49/2 ( 2 + 98) = 49 × 50 = 2450

 

Examples: 

1. 2546 + 5480 + 3210
Here add all first digits in step 1, and then add all second digits and then 3rd digits and so on as shown below.
2546 + 5480 + 3210
10000 + 1100 + 130 + 6 =          11, 236.

2. 256 + 516 + 310.
1000 + 70 + 12 = 1082.

3. 5467 + 6752 + 8971 +8605.

4. 679 + 760 + 896
Add all first digits in step 1, and then add all second digits and then 3rd digits and so on as shown below.
2100 + 220 + 15.
2335.

5.6587 + 6540 + 5555 + 2345.
19000 + 1800 + 210 + 17
add  from right to left,
21, 027


IBPS Shortcut Formulas useful to solve simplifications faster.

  1. (a3 – b3) = (a-b) (a2 + ab + b2)
  2. (a3 + b3) = (a+b) (a2 – ab + b2)
  3. (a + b)2 + (a – b)2 = 2( a2 + b2)
  4. a4 – b4 = (a –b) (a+b) (a2 – b2)
  5. (a5-b5)=(a-b) [a4+a3b+a2b2+ab3+b4].

Sum of first n odd numbers

= 1 + 3 + 5 + ………… + (2n-1)= n2

Sum of first n even numbers

= 2 + 4 + 6 + …………+ 2n = n (n+1).

Sum of first n natural numbers

= 1+2+3 +4 + ……..+n = n(n+1)/2.

Sum of squares of first n natural numbers

=12 + 22 + 32 + 42 + 52 + 62 + …………+n2.

= [n (n+1)(2n+1)]/6.

Sum of cubes of first n natural numbers

= 13 + 23+33 + 43 + …… + n3

= [n(n+1)/2]2

1 + 2/3 + (2/3)2 + (2/3)3 + ……(2/3)n= 1/(1 -2/3)n

1/1.3 + 1/3.5 + 1/5.7 +.……. + 1/[(2n+1) (2n-1)] =?

Shortcut method:

1/gap [1/first – 1/(2n-1)]= n/(2n+1)         last number = 2n-1 =7

= 2n=8

=n=4.

= 4/(2*4 + 1) = 4/9

Geometric Progression: When the sum looks likes as below we have to find the total sum by using formula.

a + ar2 + ar3 + ar4 + …………… + arn

 = Total sum = a (1-rn)/ 1-r.  [ a = first number]

Example: 2 + 2×32 + 2×33 + 2×34 + 2×35

= 2( 1- 35)/1-3

= 2( 1- 243)/(-2)

=242

Athematic Progression:

The sum of a, (a+d), (a+2d), (a+3d),……… (a+(n-1)d)

Total sum = n/2 [2a + (n-1) d]

= n/2 (first +last).

What is the sum of all even natural numbers below 100

2 + 4+ 6 + 8 + 10 +……+98

Formula:

Sum =n/2 (f + l)      [n = total numbers, f = first number, l= last number].

= 49/2 ( 2 + 98) = 49 × 50 = 2450



Here, we can split 12 as 4×3
Ans. is 4 .

Here, we can split 12 as 4 × 3.
we take small number 3 as answer.

Formula:

A(2 ^n  -1)/2^n)

3(2 ^4  -1)/2^4)

= 3(15/16)

 = 6

sqrt|  4 + 5/16 + 6/25 + 7/36   ( solve from right to left)

Explaination:   ( sqrt (49) = 7, then 7+ 29 =36, sqrt(36) =6, 6+19 =25, sqrt (25) =5…..)

sqrt(4 +5) = sqrt(9) = 3

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