Y2 dd says she's been told off for using a number line when taking away as is should be in her head,what strategies should she be using instead?

[MrsHeffley]

TIA

Sorry bit of a garbled thread title,was in a rush.

Basically I think she's supposed to be doing it all in her head but she doesn't seem to know which strategies to use.She's been moved down a group(I wasn't told),is devastated as she says the group she's in is too easy.Says she's been sneaking back to her old group .

Would like to do some with her at home but not sure what.

I think she's got a student at the moment.

Depends on the calculations she is being asked to solve! She should be able to partition, halve, subtract 10 plus or minus 1, count back, count forward to find the difference etc. She needs to develop the skill of deciding which strategy is the most effective for the calculation she is trying to solve

How do I help her to develop the skill to decide?Could you elaborate a bit more on partitioning?

Many thanks!

The numberline strategy can easily be used as a mental strategy (ie picturing the line and the jumps in your head), but if she is not ready for that yet and needs to see it written down, then there is no point forcing her to do it mentally.

As a student I was guilty of trying to push children onto using mental strategies before they had a full grasp of what they were doing, as I believed that they were holding themselves back and wouldn't make progress if they weren't pushed. Having more experience now and working with yr5/6 bottom sets who didn't spend enough time doing calculations with objections, number lines etc. I now know that isn't the case!

I would recommend spending time using whatever strategy she finds the easiest at home, the more she practises it the quicker she will become and should start to find that she is quicker to do it mentally than writing it down each time!

If she is calculating 126-9 you would count back, if calculating 126-119 you would count on. If working out 50-26, you would halve 50 and take an extra 1 away, if calculating 124-59, you would take away 60 and then add 1. She needs to practise the strategies and aim to work out which is the most efficient for HER ( some children naturally prefer one method to another, which is fine as long as the method is secure and efficient-she might prefer counting back but you wouldn't want to do that for 345-259! )
Partitioning simply means splitting the numbers up into place value components. So 286-135 would be 200-100, 80-30 and 6-5. ( which is OK until you have 284-135 where for units you end up with 4-5! )