Following on from yesterday's mental addition, today your tasks are going to involve mental subtraction. Both Blue group and the other group need to complete questions a-h on each section of their work.
For any questions that you have worked out mentally but are not sure on you can check your mental calculation by doing the question again with the formal written method.
Remember that in formal written method we work from right to left (start in the 1s column) but when working things out mentally you might be asked to (or find it easier to) do things slightly differently.
E.g. 268 - 70 think of a number line 198___200______________268
take away the 68 to get to the hundred then take away the 2 that is left.
As always, if there is anything that you need help with or is unclear please email.