1. LQ Are some subtraction methods better than others? RAG Key Words: Calculation, Operation, Accuracy,13-Jan-16 Starter Activity Think / Pair / Share If you know that 321 + 68 = 389, what else do you know?

2. 392 + 124 = (4 x 100) + (11 x 10) + (6 x 1) Write a comment or ask a question.

3. 392 + 124 = (4 x 100) + (11 x 10) + (6 x 1)

4. 3.92 + 12.4 = ( ) + ( ) + ( ) Would it work for decimal numbers?

5. 392 - 124 = ( ) + ( ) + ( ) Would it work for subtraction?

6. Choose a question that you can answer confidently. Write your answer on your mini whiteboard. You must show how you worked it out. 83 - 34539 - 426323.5 - 172.9122.4 - 34.71

7. Class Methods 83 - 34

8. Class Methods 539 - 426

9. Class Methods 323.5 - 172.9

10. Class Methods 122.4 - 34.71

11. Longhill School Raise Money for the RNLI The RNLI have over 4500 volunteer members. Every volunteer needs to be trained in search and rescue techniques and life saving skills. Volunteers have to go on training courses and they need to have specialist equipment and clothing. In this lesson you will be using subtraction techniques to calculate the amount of money left after some of some of these items have been purchased.

12. Peer Assessment Swap your book with someone else on your table. Ask your partner to explain their working out to you. Is it clear how they have worked out their answer? Check their answer with a calculator. If they have made a mistake can you work out where they went wrong?

13. Are some subtraction methods better than others? You must give reasons for your answer.

14. One question I would like answered… Two things I am not sure about yet…. Three things I have mastered … Plenary - Progress Pyramid