Written Calculations Parent Workshop – Subtraction and Division KS2

ResourcesPencilsWhiteboards/pens/rubbersSquared paperNumber lineRuler100 squareUnifix cubes

Why we are doing this Calculation Audit – Audit the knowledge of the children by

giving them 3 age appropriate calculations to complete in each operation. Subtraction and division were the weakest. Across the school only 48% of subtraction questions were answered correctly. 36% for division. It also showed a range of different methods used.

Data across KS2 in particular shows that Maths is a weaker area. This is apparent through monitoring including looking through books – there is inconsistency in strategies children are using.

2 key areas were identified by OFSTED which would improve the learning across the school. One of which was: Teachers do not always ensure that lower ability

learners have grasped essential concepts before moving on to more complex concepts. This is especially the case in mathematics.

Calculations policyIn September 2013 – We introduced a

calculations policy in the school. This is to ensure that everyone is clear on the different steps that will be taught in each year group for each calculation operation

It is an essential document because it ensures consistency across the school and shows a gradual building step by step to ensure deep conceptual understanding of number and not only “how to achieve the answer to the question in the quickest time”

This is available on the school website

This sessionWhat it IS

◦The purpose of this session is to inform parents of the methods we use and expect in school at each age group in KS2.

◦This is to ensure parents have the strategies to support our calculation policy at home

What it ISN’T◦A debate – The calculation policy has

been agreed by all staff and governors alike and is the result of much discussion and research

SubtractionUnderstanding how to partition numbers is

key

123 = 100 + 20 + 3456 = 400 + 50 + 6

Also (when moving toward ‘exchange’)

56 = 50 + 656 = 40 + 16

223 = 100 + 120 + 3

Partition these numbers7427674125344528

Year 2

Counting back in ones using a number line or a hundred square

Use this method to solve these calculations19 – 639 - 8 24 – 932 - 13

Year 3

Use this method to solve these calculations44 – 2684 – 3374 – 57134 - 49

Use this method to solve these calculations434 – 319746 – 437879 – 292

Year 4 – 5Expanded column method

Use this method to solve these calculations358 – 236741 – 3791546 – 687

Y5 - 6

Using the language of 150-70 OR 15 tens take away 7 tens

Use this method to solve these calculations957 – 354356 – 7492584 – 10387453 - 5327

DivisionImportant for children to

understand the difference between grouping and sharing.

There is a very clear running theme throughout which is used all the way through KS2 - groups/chunks

DivisionSharing6 ÷ 2

12 ÷ 4

Grouping6 ÷ 2

12 ÷ 4

Year 2 - 3

Use this method to solve these calculations36 ÷ 642 ÷ 745 ÷ 457 ÷ 5

Year 3 - 4

Chunking on a number line: (for larger numbers) e.g. 84÷6

Use this method to solve these calculations98 ÷ 787 ÷ 4136 ÷ 8174 ÷ 6

Year 4/5

Chunking vertically: (Taking away ‘chunks’ of a number)

Bus stop chunking

Use this method to solve these calculations276 ÷ 7532 ÷ 6379 ÷ 12477 ÷ 17

Year 6Formal Long DivisionThree steps – Division –

Multiplication – subtractionThis may be most similar to what

many are used to but there are key differences

Use this method to solve these calculations965 ÷ 8475 ÷ 12743 ÷ 14643 ÷ 18