# Mental Computation Strategies: Addition Go to Articles

It is essential that all students are able to calculate mentally as well as with paper and pencil. Students can make mental calculations quickly and easily with the help of strategies. There are mental computation strategies for each of the four operations: addition, subtraction, multiplication, and division. Strategies for addition are explained here.

See 35 + 23

Think 35 + 20 + 3

## Bridging to ten

See 17 + 8

Think 17 + 3 + 5

Synonyms: bridge the decades; bridge to ten; make a ten; make to ten; use ten

## Compensating

See 28 + 36

Think (30 + 36) – 2

Synonyms: compensation; round and adjust; round or adjust; use a nearby number

## Counting on

See 58 + 24

Think 58 + 10 + 10 + 4

Synonym: jump

Sub-strategies: count on 1; count on 2; count on 3; count on 0

Choose pairs of addends to make the calculation more manageable. This strategy applies only when there are three or more addends.

See 14 + 23 + 16

Think 14 + 16 + 23

Synonym: use compatible pairs

## Using doubles

Use a known nearby double.

See 7 + 8 = ___

Think 7 + 8 = 15 because 7 + 7 = 14

Synonym: near doubles

Sub-strategies: double plus 1; double plus 2

## Using place value

Expand the addends into places before adding the value of the digits in each place.

See 56 + 17

Think 50 + 10 + 6 + 7 or 6 + 7 + 50 + 10

Synonym: split

(For doubling)

Split one of the addends into places, double the value of the digits in each place, then add the doubled values.

See 12 + 12

Think double 10 + double 2

##### From The ORIGO Handbook of Mathematics Education, 2007, ORIGO Education

These addition strategies, as well as strategies for subtraction, multiplication, and division, are explained in The ORIGO Handbook of Mathematics Education.

## Bibliography

Burnett, J. (2001). Mastering mental maths: Addition. Brisbane, Australia: Prime Education.

Burnett, J., & Irons, C. (2005). GO maths teacher sourcebook: Level 2B. Brisbane, Australia: ORIGO Education.

Irons, C., Burnett, J., & Turton, A. (2007). The book of facts: Addition. Brisbane, Australia: ORIGO Education.

The ORIGO handbook of mathematics education. (2007). Brisbane, Australia: ORIGO Education.

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Maths Made Easy:Thinking Strategies in Primary Mathematics *Article by Dr Calvin Irons As published in...