His teacher has told me how frustrated she is with him. He usually knows the answer, but his written work doesn't reflect this. I've started getting him to practise at home (yr6 SATS in a few weeks) and I understand her frustration!
E.g. in a comprehension question, "Is the author and adult or a child? Support your answer with a quotation from the text" he provided the quotation, but didn't actually write "the author is a child"
All his answers are as brief as possible and he'll often miss the 2nd mark, even when he knows perfectly well what the answer was, simply because he didn't write a full enough answer. His teacher has been battling with him over this, so I don't suppose I'll have much more success, but what can I do to help?
Maths is the same, in a question like one apple costs 23p, If Johnny buys 8, how much change will he get from £5. DS1 will work out what 8 cost, but "forget" he needed to work out the change, which he can do easily in his head when reminded.