Using You Reckon?

Materials can be used as:

• a coherent block of lessons (taking about 3-5 hours to complete)
• as individual lesson plans that can be used as 'samplers'
• as 'sprinklers'
• and as 'one liners' that can be used as short 10-15 min free standing activities, and for homework.

Each lesson begins with straightforward tasks, then presents increasing challenges. Within any lesson, there are challenges appropriate to a variety of levels of attainment. We discuss pupil progression in the FAQ section.

We suggest you show the You Reckon presentation as a way of introducing the ideas of plausible estimation. There are two versions - one has the slides automatically advancing after a brief pause and the other will advance on the click of the mouse. One approach would be to play the automatic version once or twice so the pupils see the range of statements and claims involving large numbers in different contexts. You may then want to move straight into the first PE task, or to use the manual advance version to have a brief discussion about reactions to these claims - are they believable?, what are they based on?

You might also want to use this presentation as a concluding activity to wrap up PE - where you might expect a more critical evaluation of the claims.

The lesson block starts with Heart Beat, which asks how many beats a 14 year old heart has made, and introduces the language of Plausible Estimation and some of the big ideas. Stop! Thief! requires pupils do some estimation and measurement to arrive at what might at first seem an unlikely conclusion, that the thief is actually the bank manager, not his imaginary 'armed youth'. In Olympic Opening Ceremony, pupils act as consultants to the Olympic Committee, making judgments about whether all the athletes can stand in the centre of the Olympic track. In Biofool they estimate the amount of biodiesel that can be produced from set aside land; they also work out what proportion of current agricultural land would be needed to provide all the biofuel needed for road transport. Splash Down is an extended piece of work that asks about the amount of water that can be gathered from the school roof.

These tasks can be taken in order, with all the students working on the same problem at the same time. Another approach which has worked well is to start off with Stop! Thief! and with the whole class, and then have different groups in the class tackle one of the other tasks (or one of the 'sprinklers' [Simple, Simon?, Chain Gang, Mellow Yellow, Congaratulations]) and do a short report on their findings to the rest of the class. This way, all the pupils meet a range of contexts but without spending too much time, and have the opportunity to develop skills in talking about mathematics and how it can be used in everyday situations. 'One liners' can be used at any time after some initial exposure to PE tasks. We hope you will find and invent your own 'one liners' to pepper your lessons with some examples of the power of simple mathematics! If you do, the Smart Centre would be delighted to hear from you.

There are opportunities for practical work, homework, and extended projects, here.

Plausible Estimation in Class

Teachers' Notes provide detailed suggestions on how to structure classroom activities. The following section offers some guidance relevant to using any PE task - so should be particularly helpful with the 'sprinklers' and 'one liners'.