Number: Video playlist

Kate and Joe get caught out when they fail to appreciate that measurements are approximate. The carpet Joe has bought doesn’t fit. Maths Crimes Detective Al Gebra explains why, by finding the upper and lower bounds for the measurements they have been given and manages a clever cover-up.

Set questions on finding upper and lower bounds for varying degrees of accuracy. The application of these to problems where deciding the correct bound to use for a particular purpose is essential. When adding or multiplying, eg to find greatest and least perimeter or area for a rectangle both upper (or both lower) bounds are needed. However, when subtracting or dividing, eg to find greatest or least difference or greatest or least speed the choice of bounds needs to be thought out more carefully.