You may also like

problem icon

Prompt Cards

These two group activities use mathematical reasoning - one is numerical, one geometric.

problem icon

Consecutive Numbers

An investigation involving adding and subtracting sets of consecutive numbers. Lots to find out, lots to explore.

problem icon

Exploring Wild & Wonderful Number Patterns

EWWNP means Exploring Wild and Wonderful Number Patterns Created by Yourself! Investigate what happens if we create number patterns using some simple rules.

Two Egg Timers

Stage: 2 Challenge Level: Challenge Level:2 Challenge Level:2

Why do this problem?

This problem offers opportunities for children to practise addition and subtraction. It can be approached in many different ways so could give learners the chance to share different methods and discuss which may be more efficient.

Possible approach

Children could work in pairs on the problem. You could collate their findings on the board and encourage them to try to look for ways to make the times that haven't been achieved.

After a suitable length of time, invite them to share the ways they have been working. Some might have used a trial and improvement approach - seeing what numbers they can make using particular combinations of the timers. Others may have used a method for choosing the order the timers are used in. Some might have tried to find a way of making 1 minute, then 2 minutes, then 3 minutes etc.

In the plenary, if it hasn't come up already, ask how having a way of making 1 minute might help.

Key questions

Can you use any of the times you've made so far to help with others?
Do you have a system for trying out your ideas?
Why would it help to have a way of making 1 minute?