Many students want to know how to solve approximation aptitude questions easily in competitions like SSC, IBPS, SBI, GATE, CAT, JIIB etc. In this tutorial you will get best way to solve approximation aptitude questions answers that save your time as well as allow you to score more marks.
The simplest and best way in approximation is to choose the closest number by neglect the rightmost digit of number (or after decimal point ) according to the given Tips and tricks :
- If the value is less than 5 consider it as zero for example 4.04 will be written as 4.0. Here the second number of decimal is less than 5 so it is consider as 0.
- If the value is equal to or greater than 5 increase, 1 in left digit for example 4.06 will be written as 4.1. If we further apply approximation to this number than we get 4.0, because this time 1 is less than 5 .
This was the Basic rule of approximation by which you can solve any type of approximation problem very easily.
Approximation in addition :
Take an example : Add 1958.005 + 20.886
In this example first digit is 1958.005 here the 3rd digit of decimal is 5 that means we can neglect it by increasing 1 in the left side. After approximation the new number is 1958.01. Now we can apply another step of approximation, but this time the second decimal digit 1 is lower than 5. So we will neglect it and our number will become 1958.0 .
In this example second digit is 20.886, Here third digit on right hand side of decimal is greater than 5 so we will add 1 to the right side digit and neglect it. The new number will become 20.89. Now if we again apply approximation than we will get 20.9. In the third step of approximation the first digit at right of decimal is 9 that is greater than 5. So it will be neglected and by adding 1 to the left side, the number will become 21.0
After approximation our numbers are : 1958 + 21 = 1979
You can also apply approximation to the result in same way :
- The number will be modified as – 1980
- Again approximation – 2000 ( Final value )
Short Tricks for exam
- Consider only first right digit to decimal
- For example if number is 2586.06589 – Directly write it as 2586.0 Because after approximation the first right digit will be 1 and that is lower than 5.
- If number is 2365.89002 write it as 2366.00 because at this time the first right digit is already greater than 5.
Example 2 : Add 5689.7656 and 5694.3569
After approximation the numbers will become 5690.0 and 5694
So 5690 + 5694 = 11384 ( approximately )
Approximation in Multiplication : Approximation questions with multiplication also solve as addition. So we are directly going through an example
Example 3 : 58.86 × 31.268
Answer : In this example first number is 58.86 here the first right term from decimal is 8 i.e. greater than 5. So we can directly add 1 to left side after neglecting decimal digits . The number will become 59.
But still you can use another approximation to simplify it 59 to make it 60.
The another number is 31.268, Here you can directly write it as 31.0. If you want to take again approximation of this value than make it 30.
Now we can easily find the multiplication of 60 and 30
=> 60 × 30 = 1800 ( approximately )
Note : During your examination check the closest answer if there is an option of 1860 i.e. 60 × 31 = 1860. Then you have to choose it for your answer.
Approximation in Division:
Example 4: Find the value of 889.056 ÷ 9.466
Answer: Here first number is 889.056, in this case you can easily visualize 0 is coming in first right digit of the decimal. So neglect the all decimal numbers and write the number as 889.0, Still you can apply another approximation and make it 890.
Second number is 9.466 you can easily visualize that after first approximation then number will become 9.5, Now we can again use approximation and this number will become 10.
Now you can easily solve 890 ÷ 10 = 89 .
Note : If 89 is not in the options then select 90 as correct answer but never choose 87.