How do we know how many decimal places to round our answers to in both CM1A and CM1B? Additionally, is CM1B marked by a program? Because I sometimes use certain methods to calculate answers that may give a slightly different answer (e.g. the answer is the same all the way to the 13th D.P.). Thanks
The general rule for Paper A is to only round your final answer, ie don't round intermediate calculations, but save the numbers in your calculator memory for use in further calculation steps. When writing out numbers, I usually go for at least three decimal places or four significant figures unless the question states otherwise. As far as I'm aware, Paper B is marked by humans and not a program. You're allowed to use different calculation methods from those on the marking scheme and if your method is valid then you'll get full marks!
