Mental Addition

Tiffany with rucksack

 

Mental addition means adding two or more numbers together in your head (without using pen and paper)

Being able to add numbers together in your head is a good skill to learn and will save time

There are a number of different tips and tricks to help with mental addition

 

 

Know Your Number Bonds

If you know your number bonds to ten then you will know immediately that

8 + 2 =10

If you know your number bonds to twenty then you will know immediately that

15 + 5 = 20

If you know your number bonds to one hundred then you will know immediately that

30 + 70 = 100

You can learn number bonds to any number - 10, 20, 30, 40, 100, 1,000 etc

 

Break Numbers Up (Chunking)

If you are asked to add together 45 and 36 in your head it is much easier to add together 45 + 30 + 6

45 + 30 = 75 + 6 = 81

Similarly, 226 + 133 is much easier as 226 + 100 + 30 + 3

226 + 100 = 326 + 30 = 356 + 3 = 359

 

Add Numbers in Stages

This method is particularly useful if you have to add up a lot of single digit numbers

If you are asked to add together 1, 6, 8, 5, 1, and 9

you can do this as

1 + 6 = 7 + 8 = 15 + 5 = 20 + 1 = 21 + 9 = 30

or

1 + 6 = 7 + 8 = 15

and

9 + 1 = 10 + 5 = 15

so

15 + 15 = 30

 

Adding The Numbers 1 2 3 and 4

The numbers 1, 2, 3 and 4 can be quickly added by using the way the numbers are formed

1234 quick counting

Number 1 is counted as 1 - it is often written without the hook at the top making it a single stroke

Number 2 is counted as 1, 2 - one for each of the two strokes as shown

Number 3 is counted as 1, 2, 3 - one for each of the three parts as shown

Number 4 is counted as 1, 2, 3, 4 - one for each of the four parts as shown

Using this method the sum 1 + 2 + 3 + 4 would be added by counting all the individual strokes of each number - 1, 2, 3, 4, 5, 6, 7, 8, 9, 10

 

Harvard Reference for this page:

Heather Y Wheeler. (2015). Mental Addition. Available: http://www.tiffanymacbeth.com/Maths/mental_addition.htm. Last accessed


Maths Topics



  

Page last updated 02/04/2016

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