Maths workshop – Subtraction

Monday 22nd March 2010

The National Numeracy Strategy provides a structured and systematic approach to teaching number. There is a considerable emphasis on teaching mental calculation strategies and speaking and listening activities. Informal written recording always takes place regularly and is an important part of learning and understanding. More formal written methods should follow only when the child is able to use a wide range of mental calculation strategies. This will help communicate methods and solutions.

Stages in subtraction (these are not necessarily hierarchical)

• Informal counting strategies e.g. counting songs, rhymes and games

• Practical and pictorial subtraction

• Use of number lines to count back from one number to another

• Finding the difference between groups of objects or numbers

• Using an empty number line to count back

• Using an empty number line to count up

                                                 

Stages in Subtraction by Decomposition

563 - 241 :

500 60 3

- 200 40 1

300 20 2 = 322

leading to:

5 6 3

- 2 4 1

3 2 2

563 – 278:

500 60 3 400 150 13

- 200 70 8 200 70 8

200 80 5=

285

leading to:

4 515 6 13

- 2 7 8

2 8 5

Children’s own recording

Vocabulary

Subtract, subtraction, minus, take away, less, leave, fewer, decrease, difference

Equals

Number sentence

Record, draw, show me, jottings

Sum!

                  

Resources to help children with subtraction

                         

Ideas for subtraction activities at home

•Counting back in 1s, 2s, 5s, 10s, ……. from different starting points

•Using/making number lines to count back or count up

•Finding the difference between groups of objects e.g. toys

•Playing shops and giving change

•Solving subtraction problems

•Encouraging children to record subtraction problems in their own way and explain them to you

•Asking children to talk you through the methods they have used at school

Any questions?

Please feel free to look at the children’s work, resources and maths vocabulary on display.

Miss Seare and I will be pleased to speak to you afterwards if you have any further comments or questions.