Transcript Slide 1

LQ Are some subtraction methods better than
others?
Key Words: Calculation, Operation, Accuracy,
RAG
21-Jul-15
Starter Activity
Think / Pair / Share
If you know that 321 + 68 = 389,
what else do you know?
392 + 124 = (4 x 100) + (11 x 10) + (6 x 1)
Write a comment or ask a question.
392 + 124 = (4 x 100) + (11 x 10) + (6 x 1)
Would it work for decimal numbers?
3.92 + 12.4 = (
)+(
)+(
)
Would it work for subtraction?
392 - 124 = (
)+(
)+(
)
Choose a question that you can answer
confidently.
Write your answer on your mini whiteboard.
You must show how you worked it out.
83 - 34
539 - 426
323.5 - 172.9 122.4 - 34.71
Class Methods 83 - 34
Class Methods 539 - 426
Class Methods 323.5 - 172.9
Class Methods 122.4 - 34.71
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.
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?
Are some subtraction methods
better than others?
You must give reasons for your
answer.
Plenary - Progress Pyramid
One question I would
like answered…
Three
things I
have
mastered
…
Two things I am
not sure about
yet….