UNCORRECTEDSAMPLEPAGES

2F Choosing the right calculation

It is critical to understand calculations when we read and interpret numerical and quantitative information. We need to know, for example, when to use addition (+) or subtraction (–) or multiplication (×) or division (÷), which are the four main maths operations. Similarly, we need to know how to work out calculations with fractions (e.g. 1 2 or 3 4 ) or percentages (e.g. 10%, 25% or 2.75%) or rates (e.g. $12.50/kg).

This relates directly to the first stage in our problem-solving cycle – Formulate.

When solving a problem in the real world, the first thing we need to do is understand the context of the problem and decide which maths we need to use – what we call, formulating the problem.

Knowing which operation to use

Let’s do a recap of the different maths operations and their meanings and symbols. An operation is a mathematical process. The most common ones are add, subtract, multiply and divide (+, −, ×, ÷). But there are many more, such as squaring a number, finding a square root of a number, cubes and powers.

Here are some explanations of the common operations.