1. Chapter 6 Number: Calculation (addition, subtraction, multiplication, division)

2. Chapter Summary
The chapter makes the link between mental calculation strategies and more formal written methods
It suggests that mental methods should always be a first resort
It emphasises the importance of children approaching calculation practically and through activity.

3. Starting point
Carry out the following calculations mentally = = 48 – 15 = 107 – 99 = 26 x 5 = 44 x 4 = Talk to a partner. Discuss the strategies that you used

4. Good practice in primary mathematics
Children should focus on practical activities and developing mental methods in the early stages of their time in primary school.
A good understanding of place value and the ability to recall multiplication tables and number bonds supports effective calculation.
Your learners’ confidence and fluency in calculating will be improved if you place a string emphasis on problem solving and make the most of cross curricular links
A focus on misconceptions will make sure these do not develop and impede next steps in learning
(Ofsted: Good practice in primary mathematics: Evidence from 20 successful schools)

5. Multiplication and division as arrays
This array shows
8 x 4 = ÷ 8 = 4
4 x 8 = ÷ 4 = 8
What number facts can you show with arrays consisting of 24 dots? What about 36 dots?

6. The progression of children’s development of mental methods
Adding and subtracting pairs of single digit numbers
Adding single digit numbers to multiples of 10
Adding and subtracting groups of numbers
Adding and subtracting 3 digit numbers from multiples of 10s and 100s
Multiplying 3 single digit numbers
Using place value, known and derived facts to multiply and divide mentally.

7. Portfolio task
Use mental methods to carry out the following calculations. 36 x 9 = 52 x 6 = 84 x 3 Derive at least five new facts from each calculation.

8. Observing the teaching of calculation
Watch the video ‘How many peas fill the classroom?’ on the companion website. Imagine that you are giving the teacher feedback. What are three strengths that you saw in the teacher’s practice? What is an area you would like them to develop? How would you adapt this activity for use in youyr classroom?