Mental Math Subtraction Strategies | Mental Math Tricks for Subtraction | How to do Mental Math Subtraction?

Are you facing any difficulty in doing subtractions mentally? Then you have landed on the correct page where you will find plenty of strategies in the subtraction process. This article includes the tricks to do the subtractions mentally in the head very fast. These tricks save time in the competitive exams which are very helpful for the students. You can also check the solved examples of mental math subtraction for a better understanding of the concept.

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Mental Math Subtraction

Here we will discuss the tricks for doing the subtractions mentally. Practicing these tricks will help you in doing subtractions mentally very fast and accurately. Use these tricks to do subtraction and sharpen your skills in Mathematics.

Subtract in Two Parts

Subtract the previous whole ten, then the rest.
Example:
55-9
Solution:
subtract 9 in two parts. they are 5,4.
=55-5-4
Subtract first 5 then 4.
=50-4
=46

Subtract in Parts

Break the subtrahend into its tens and ones. subtract in parts.
Example:
45-23
Solution:
Break subtrahend i.e. second number into tens and ones.
=45-20-3
Subtract tens and then ones
=25-3
=22

Use Known Subtraction Facts

since 13-6=7, we know that 53-6 will end in 7. But it will be in the forties something. So it is 47.
Since 15-9=6, we know that 45-9 will end in 6. But it will be in the thirties. So it is 36.

Add
we can add backward. When the two numbers are close to each other this technique works well. Instead of subtracting, check how much you add to the subtrahend in order to get the minuend
Example:
70-68=?
Think 68+__=70
Add UP to find the Difference
To find the difference, first, start at the small number and add up until you get to the larger number.
Example:
85-48
48+2=50
50+30=80
80+5=85
we added 2,30,5 i.e. total of 37.
85-48=37.

Subtract an easy Number that is Closer and then Correct the Answer

First, subtract an easy and closer number and then correct the answer.
Example:
34-18=?
since 20 is closer to 18 and easy to subtract 34-20=14. But you subtracted two too many. So add 2 to the answer. i.e. 14+2=16.

Compatible Numbers

It will work well for powers of 10.
Example:
100-34=?
x+34=100
x=100-34
x=66

Equal Addition Strategy

You can add the same number to the subtrahend and minuend for subtracting.
Example:
54-28
Add 2 to both numbers
54+2=56
28+2=30
56-30=26

Subtract from Left to Right

Start subtracting from left to right one digit at a time. Borrow numbers when necessary.
Example:
subtract 4311 from 9542
9   5    4   2
-4   3   1   1
5    2    3    1

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