I missed out on 2 marks in science because I didn't write down the correct equation for me to rearrange it and then substitute the numbers in. I did it on higher tier but not on foundation. I also can't do separate papers higher and foundation, I am more comfortable with combined science papers. What I did was invent my own equation with what the question was asking for as the subject of the formula and substituted it Guess it could be because I went more stupid and other factors and it's good I did foundation.