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Mental computation

The importance of mental computation has been identified by a considerable body of research.

It has been found that nearly 80% of all calculations by adults are carried out mentally, and that frequently estimation is sufficient.

Approaches to calculation in school should reflect the demands of everyday life, as explained in the article Put Mental Computation First? on the AAMT website.

Research also indicates that an emphasis on mental computation can improve students' development of number, while an early introduction to formal written methods can harm it.

The Australian Curriculum: Mathematics includes mental strategies as well as written and technology-based methods.

Mental strategies provide an important window into students' understanding of number.

Big ideas

The big ideas underpinning mental computation include key number knowledge, being able to generalise patterns and relationships, developing fluency and flexibility, and thinking strategically.


Misunderstandings can be countered by building knowledge – which is the easy recall of associations. Understanding implies being able to justify why a property works or does not work.

Good teaching

Good teaching of mental computation provides learning experiences for students that build fluency and flexibility in carrying out calculations in their heads.


Assessment is not just for reporting achievement at a particular point. Modern approaches to assessment advocate using data about students to inform learning and teaching.


Student activities that appear in other parts of the drawer have been collected here.


All downloadable files, such as student worksheets, teacher notes, activity templates and video transcripts, are available here.


The Mental Computation drawer was written by a team from the Mathematics Teaching and Learning Research Centre of the Australian Catholic University, led by the centre’s Director, Prof. Doug Clarke.