Step 8 Objective

Use systematic trial and improvement methods and ICT tools to find approximate solutions to equations such as x³ + x = 20.

Examples of what pupils should know and be able to do

Pupils should be able to use trial and improvement for equivalent problems, e.g. A number plus its cube is 20; what’s the number?

The length of a rectangle is 2 cm greater than its width.
The area is 67.89².
What’s the width?

Pupils should have opportunities to use a spreadsheet for trial and improvement methods.

Probing questions

How do you go about choosing a value (of x) to start?
How do you use the previous outcomes to decide what to try next?
How do you know when to stop?
How would you improve the accuracy of your solution?
Is your solution exact?
Can this equation be solved using any other method? Why?

What if pupils find this a barrier?

Working with problems in context can help pupils understand the process, for example Max box.