My DS1 is learning Maths with the Heinmann (?) Scheme. He has been getting on great with it, Maths seems to be one of his strengths. However he brought home some homework that was taking away from 11 and 12, ie 12 - 5 = ? or 11 - 7 = ?, and he is struggling because he has run out of fingers. He couldn't remember how the teacher taught them to do the sums and anything I suggested was "too difficult" or "not right".
Would greatly appreciate if anyone could advise on the correct (if there is such a thing) way to do these sums so that I will be able to help him next time.
TIA.