Why do this
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.
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
In the plenary, if it hasn't come up already, ask how having a
way of making 1 minute might help.
Can you use any of the times you've made so far to help with
Do you have a system for trying out your ideas?
Why would it help to have a way of making 1 minute?