Estimation and Approximation contains explanations, examples and exercises beginning with rounding numbers to powers of ten, rounding to a certain number of significant figures and rounding to a number of decimal places. The exercise contains many questions set in different contexts such as measuring lengths of rivers, weights of rabbits and length of throws in an athletics competition. Estimation requires students to estimate the answer to a calculation, use a calculator to find the exact answer and compare the two answers before progressing to explain a ‘formal’ method of approximation by rounding each number in the calculation to one significant figure. Different methods of approximation are compared when dealing with estimations involving square roots.
The activity sheet includes an activity in which students have to choose which of the suggested answers is the best approximation to the answer to a calculation.