Supporting the effective use of ICT across the primary curriculum
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Mathematics Age 6-7: Guess my number! Introduction: This lesson is about ordering numbers in the context of a game. The children have to guess the number (between 1 and a 100) that the computer has selected. Each time they make a guess the range is narrowed down. The number of guesses is recorded. The lesson is in the form of a game where the children have to develop a strategy – namely selecting a number that is halfway along the range. This may seem an obvious strategy to adults but children will usually be much slower in grasping this idea. Resources One PC linked to an interactive whiteboard for whole class work The Guess my Number program which can be accessed from: http://www.amblesideprimary.com/ambleweb/mentalmaths/guessthenumber.html It is also useful to have a visualisation of the number line. This can be accessed from: http://nationalstrategies.standards.dcsf.gov.uk/node/104052 Open a second copy of the web browser in order to access the ‘number line’ and choose the option that says Download as a windows executable file. Previous learning Children should have experience of place value in numbers up 100 They should be able to compare the relative size of two numbers Learning Objectives Children will: learn to recognise the relative size of numbers decide which number to choose in the light of the information displayed on the screen begin to think strategically so that the number of guesses is kept to a minimum. What to do This is a whole class lesson. The children are invited to guess the number that the computer has generated and the number of guesses is recorded. Initially the children will just guess (and may strike lucky – in which case get them to choose your next lottery numbers!). However they should be encouraged to explain why they have chosen a particular number. Note that both the numbers 1 and 100 can be changed to different values. It is useful to have both programs mentioned above open on the task bar so that you can swap from one to the other. The one program gives the children feedback as to whether they are guessing too high or to low, whilst the other one provides a visual picture of the number line (set the Max button to 100) and they can see the range between which the number lies. There are two pointers on the number line; keep moving them so that they reflect the current range that the children are considering. Some children will need the number line to find the half way mark – in effect by measuring where the mid point is whilst others may be able to calculate it mentally. This visualisation will help them to reach the conclusion that perhaps the best strategy is to go for the half way mark. One of the key aims of the lesson is mathematical dialogue, encouraging children to predict and to make clear their reasoning. Do they eventually get to the point where they realise that the first guess should always be 50 regardless of what pre-conceived notions they might have? Differentiation See above. In effect the children are practising their ordering skills in a games situation whilst also thinking about the relative size of numbers. Some children might benefit from restricting the range from 1 to 20 whilst others may be able to cope with the introduction of negative numbers, perhaps setting the range from -50 to 150. © ictopus ltd
lessons2go
Maths Age 6-7: Guess my Number 2009
The role of ICT This task could be completed without the use of ICT but the process is more motivating with children trying to beat the computer, whilst at the same time seeing a ‘picture’ of how they are focusing in on the number line – in effect trapping the number. Follow-up suggestions This is a one off activity. It could be followed up with similar activities where the range of numbers is extended or simplified. Both programs allow for the range of numbers to be modified (to a realistic maximum of 500). The notion of randomness could also be explored. If the computer chose a large number on one turn, are the children more likely to guess at a small number the next time round? Assessment How did the children decide what number to choose? About how many guesses does it take on a successful run and how many on a poor run? Can they describe the best strategy to a friend? Is there a guaranteed number of guesses by which the missing number will always be discovered? The more able children might like to reflect on what happens when the range is doubled (i.e. 1–200) – is the average number of guesses doubled or is it just increased by 1?
This lesson idea was first published as part of the Becta Direct2U subscription service for teachers, (c) Becta, 2005-2006
© ictopus ltd
lessons2go
Maths Age 6-7: Guess my Number 2009