Portraits of Progress Making Great Progress at KS2

Associated Teachers TV programme

Portraits of Progress – Making Great Progress at KS2

Maths Lesson Plan

LESSON OBJECTIVE To use strategies to apply estimation in real life situations

KEY VOCABULARY Estimate / estimating Approximately Strategy Units of measure (e.g. m & cm, hours & minutes etc) Rounding Region (i.e. “in the region of”)

STARTER Display 1st part of Lesson objective “To use strategies to apply estimation” Remind the children how we have been using approximation to help us calculate quickly. Reinforce that it’s about using clues to help us estimate an answer – being a maths detective. It is NOT the same as guessing. Play who wants to be a maths detective (PowerPoint game). Class play along by writing their strategy on white boards Child to explain strategy used for approximation If the child is unable to explain or they can choose a member of the class to share what is on their white board.

MAIN TEACHING SESSION Display the whole Lesson objective state the focus of today’s lesson. Explain that children will be working in pairs on real life scenarios for which they can use the skills they have been learning for estimating (NB group the children with different abilities). Because it’s nearly Christmas there are lots of things to prepare. Imagine that you are going to help with the planning for some of the Christmas events that are coming up in the next few days before we break up for the school holidays. Emphasize that we will be estimating to assist with the planning meetings – but absolutely no guessing! We won’t actually be ordering anything at this stage, just using out maths detective skills to work on the preliminary planning to gauge how the events work. Therefore we do not need to achieve precise calculations in this lesson, instead we need well thought out estimates. Tell the children that they will be working on a variety of ‘scenarios’ in their pairs but first we will have a look at one together to make sure that everyone understands the type of process we will follow. Show the children a jar full of identical sweets that is sealed. Explain that Mrs Short would like to give one of these jars to each class as a Christmas treat. Mrs Short is keen to check that there will be at least 2 sweets each for everyone in the class, however the jar is sealed so we can’t count them. Say we need to devise a strategy for estimating the number of sweets in the jar? Say we can begin by considering how many sweets are in one layer. Show photograph of bottom layer and ask children to approximate the number of sweets in the bottom layer. (E.g. 12 on the bottom layer, not all of the layers will be the same so approximate 10 on each layer to make our calculations are easy.) How we could use this information to estimate the number of sweets in the jar? Show a photograph of the side of the jar and invite the children to help estimate an approximate number of layers. Use this information to estimate the number of sweets. (E.g. approximately 7 layers so 10x7=70 sweets) Now we have arrived at an estimate for the number of sweets in the jar, we need to consider if there will be enough for at least 2 for everyone in the class. How many children in the class – approximately 30 How many sweets needed for everyone to have 2 each? (approximately 2x30 =60) Are there enough? Yes, there are more than enough.

PRACTISE AND CONSOLIDATION The children will open their detective packs that will contain the scenarios that they will be working on in their pairs. Reinforce Estimating is not guessing They need to consider their problem carefully to work out an appropriate strategy to estimate the answer Strategies need to be recorded appropriately so they can explain them to others The children need to use appropriate vocabulary The scenarios will be provided in envelopes containing all of the background info, prompts and space for recording strategies. (See appendix for resources) While the children are working, encourage them to explain their ideas carefully to each other and to record ideas etc. Assist children who are struggling to get going with additional prompts

PLENARY After children have had enough time to work on their problems a selection can be shared with the class Reinforce need to use correct language and to speak in clear sentences Encourage children to explain their strategies and to show where they have approximated to achieve an estimate Ask the children to consider the advantages of estimating over calculating precisely Ask when is it appropriate to estimate? When an accurate answer is not needed or as an approximate guide When a precise calculation is not practical [In order to check the reasonableness of the answer to a calculation.] Referring to one or two examples that the children have shared Why it is sometimes necessary to refine an estimate to ensure a calculation achieves greater accuracy. Use pictorial cues (e.g. the cook who has run out of chocolates for the school’s Christmas Dinner, or a person who is shopping on a limited budget and can’t go over) Suggest ways that we might take this into account in our estimates (e.g. rounding the prices up if we are shopping on a strict budget or rounding the number of people who can share a cake down so we have enough for everyone).

POSSIBLE EXTENSION ACTIVITIES refine the strategies to allow a more precise estimate refer back to examples where the children did this as part of their strategy e.g. compensation methods to account for the approximation Practise knowing when it is appropriate to estimate Selecting appropriate strategies for approximation including when to avoid being embarrassed at the till or under catering fir food etc Considering margin of error Applying estimating to checking precise calculations.

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