8 Formulas

Figure _unit2.8.1 Figure 20 Formulas

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Illustration showing examples of formulas.

Figure 20 Formulas

Before diving in to this topic, you first need to learn about the order in which you need to carry out operations. Have you ever seen a question like the one below posted on social media?

Figure _unit2.8.2 Figure 21 A calculation using the four operations

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Illustration showing the text ‘What is the answer?’ and the sum ‘7 + 7 ÷ 7 + 7 x 7 – 7’.

Figure 21 A calculation using the four operations

There are usually a wide variety of answers given by various people. But how is it possible that such a simple calculation could cause so much confusion? It’s all to do with the order in which you carry out the calculations.

• If you go from left to right:

  • 7 + 7 = 14

  • 14 ÷ 7 = 2

  • 2 + 7 = 9

  • 9 × 7 = 63

  • 63 − 7 = 56

The correct answer however, is actually 50. How do you arrive at this answer? You have to use the correct order of operations, sometimes called BIDMAS.