# Plan ratio and proportional reasoning N1 by HC121104002213

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```									TOPIC: RATIO AND PROPORTIONAL REASONING                                                                N1

Notes:                     It is advisable to cover this lesson after the transformations lesson.
The main aim behind this lesson is to support students in making
connections between concepts and the use of common sense when
tackling problems.

Objective:                 Interpret and use ratio in a range of contexts; to make connections
between ratio, similarity and scale factors

Misconceptions:            Students confuse ratio with proportion. Poor use of a calculator.
Students do not understand the convention of labelling and naming
triangle ABC.

To start:
 Using a simple three part ratio question ask the students to solve the problem. See
Resource Sheet N1 for possible examples.
 Ask the students to share the different methods that they have used. Either ask them to
scribe on the board or model how each method is calculated.

Activity 1:
 Ask the students in groups, to work through the sample exam questions Resource Sheet
N1a
 They need to discuss and feedback their answers and methods this can then lead on to
creating learning points and exam techniques. For example how to spot the multiplier,
the setting out of the workings in a table, the allocation of the marks, the most efficient
method, the use of the calculator.

Activity 2:
 How can these methods help with similarity questions? Resource Sheet N1b or use mymaths.
Route to follow- www.mymaths.co.uk →
Shape and Space →
Similarity →
Lessons 3 and 6

 Consider the first question together make sure the ratios are easy– what do we know? How could
we use this method to solve this question? What are the links with scale factors? Work through
the other questions in pairs or a group.

To finish:
 Students practice on a couple of exam questions which are more complex for example involving
diagrams using parallel lines. Resource Sheet N1c or mymaths – (Route as above BUT lessons
7 and 8)

 When going through the answers get the students to look at WHERE the marks come from in these
types of questions; this will make their working more efficient.

 Finally ask the students to complete a revision card

Elizabeth Bishop & Nicola Shibli.ASK.Maths.July 2008

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