Key learning points

1. Rounding and estimation are practical maths skills.
2. They can be used to quickly estimate the cost of a project.
3. Sometimes you will need to apply common sense to rounding in context.

Common misconception

Keywords

• Upper bound - The upper bound for a rounded number is the smallest value that would round up to the next rounded value.

• Lower bound - The lower bound for a rounded number is the smallest value that the number could have taken prior to being rounded.

• Error interval - An error interval for a number x shows the range of possible values of x. It is written as an inequality a ≤ x < b