When GCSE questions ask you to estimate the result of a numerical calculation on the non-calculator paper you should proceed as follows:
Round the numbers in the problem to 1 significant figure before performing calculations.
Be careful if you have a number less than 1 for a denominator. For example, if the denominator = 0.4 then multiply the numerator and denominator by 10 so that you end up dividing by the whole number 4.
Please complete this week and self-mark from the solutions provided.