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Julie Anderson Dunedin College of Education Secondary Numeracy Project Auckland Feb 23-24 2005 Advanced Proportional: Stage 8 . Teaching sequence using the teaching model Knowledge Materials Imaging Number Properties-abstraction. Advanced Proportional Language. Proportion - Fraction
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Julie AndersonDunedin College of EducationSecondary Numeracy ProjectAuckland Feb 23-24 2005Advanced Proportional: Stage 8 Teaching sequence using the teaching model Knowledge Materials Imaging Number Properties-abstraction
Advanced Proportional Language • Proportion - Fraction • Ratio – Comparison (same measure) • Rate (different measures-80km per hour 40 slaters per square metre) • Multiplicative relationships with rates and ratios • Proportional relationships between measures
Quantities co-vary (change together) • To understand a ratio or a rate you must distinguish a relationship that remains constant when two linked quantities are changing together • The constant relationship is not directly observable
AP Strategy learning outcomes • Find proportional relationships between measures • 12 headbands are made with 15 metres of ribbon. How many headbands can you make from 25 metres of ribbon? • Convert from ratios to proportions and visa versa • Find amounts in given ratios • Four grey garden tiles are used too every three red ones. If you use 210 tiles altogether how many are grey and how many are yellow.
Ratio using Fruit Cards • Knowledge recap • Materials • Imaging • Number Properties
Knowledge recap Fraction versus a Ratio • What fraction of the group is the pear? the orange? • What fraction of the group are bananas?, apples? • How many bananas compared to the apples in the group? • What is the ratio of lemons to pears?, lemons to bananas?
Fruit Bowl Problems Apples and Oranges There are 3 oranges to every one apple in the bowl How many apples and how may oranges, if there are 40 pieces of fruit in the bowl?
Fruit Bowl Problems • 24 in the bowl? • 16 in the bowl? • 52 in the bowl? • What fraction (proportion) are apples? • What fraction (proportion) are oranges? • What is the ratio of oranges to apples?
Harder ratios Apples and Bananas 3 apples to every 2 bananas in the fruit bowl How many apples and how many bananas if • 40 in the bowl? • 25 in the bowl? • 60 in the bowl?
More Fruit Apples, bananas and oranges For every 4 apples in a box there are 3 bananas and 2 oranges How many of each fruit if • 45 in the box? • 180 in the box? • 72 in the box?
Make up Own Problems • Make up a problem that someone else can work out using three types of fruit, in a given ratio. • Challenge them to find a range of different amounts in the box. • Make up a problem using a different context that they can choose.
ImagingTransfer the model to other situations • In a school of 360 pupils there are 5 boys to every 4 girls. How many girls are there? • Joe works 3 days and Sam works 4 days painting a roof. Altogether they get paid $150. How much should each get?
Multilock block models • Colour mixes • 18 yellow with 6 blue in a mix to make a green • What mix might go into smaller pots to make the same colour?
Proportional relationships-rate • It takes 20 bales of hay a day to feed 300 sheep. How many bales would you need each day to feed 120 sheep. • How did you work it out?
Dog Biscuits • The amount of dog biscuits to be feed to a dog depends on the weight of the dog. • If the packet recommends that an 18kg dog needs 12 biscuits, how many biscuits should you feed a 30kg dog, a 10kg dog? • How did you work it out?