My dd can only do maths with the help of a calculator!
She has started GCSE and is ok on the calculator paper but is rubbish needs a lot of practice on the non-calculator one.
I think her problem is that she is still not that comfortable with basic numerical manipulations eg decimals, fractions, percentages, ratios and even times tables 
I wonder if anyone can suggest something that will help her to really get to grips with these crucial skills. I think repetition is the key.