Upload
hussein-naif
View
20
Download
1
Embed Size (px)
DESCRIPTION
Something to Think About. What are good activities for helping students to learn their basic facts?. Secondary Numeracy Project. Fraction, Decimal, Percents. Fraction Constructs. Fractions are needed when whole units are inadequate to get a job done. Part-Whole: continuous & discrete. - PowerPoint PPT Presentation
Citation preview
Fraction Constructs
Fractions are needed when whole units are inadequate to get a job done.
Part-Whole: continuous & discrete
Continuous fraction model Fractions are met as cutting up an
entire object– e.g. one quarter of an apple
This single object soon extends to multiple objects to be shared– e.g. sharing two apples between 5
people Leads to the concept that
fractions are divisions– e.g.
5
252
Discrete fraction model Fractions are met through sharing a
collection of objects – e.g. 4 kids share 12 cookies
Problems initially lead to discrete, whole number answers
Later problems merge with the continuous as “remainder” objects are cut– e.g. 4 kids share 10 cookies
Handout: A Teaching Progression for Fractions
Stages – Continous & Discrete
Any surprises?
Look at Knowledge & Strategy Tests
Knowledge Test: Fractions Stage 4 (3 sec)
9: Write one half as a fraction. 10: Write one sixth as a fraction 11: Write one third as a fraction12: Write one quarter as a fraction
Stage 5 (5 sec)13: Which of these fractions is the smallest?14: Which of these fractions is the largest?
6
1
2
1
4
1
5
1
3
1
Stage 6 (5 sec)15: Which of these numbers is the
same as eight-sixths?
Stage 7 (5 sec)16: Which of these fractions is the
same as two-thirds?17: Which of these fractions is the
same as three-quarters?
14
21
6
21
8
6
9
3
12
9
12
8
8
6
6
2
Stage 818: Which of these fractions is the
smallest? (10 sec)
19: Which of these fractions is the largest? (10 sec)
16
5
10
3
5
2
10
7
9
5
3
2
Strategy Test: Fractions Stage 2-4 (materials)/Stage 5
(facts): This cake has been cut into thirds.
Here are twelve jellybeans to spread out evenly on top of the cake. You eat one third of the cake. How many jellybeans do you eat?
Stage 6:– What is of 28?
Stage 7:– 12 is of a number. What is the
number?
Stage 8: – There are 21 boys and 14 girls in Ana’s
class. What percentage of Ana’s class are boys?
– It takes 10 balls of wool to make 15 beanies. How many balls of wool does it take to make 6 beanies?
4
3
3
2
SNP Teaching Model
Use a concrete representation (Materials/Diagrams)
Encourage imaging and visualisation (Imaging)
Push to the inherent property and generalisation (Abstraction)
How can we use this with fractions?
Fraction Strips Work in groups of 8 To start each person has a different
colour paper Fold paper in eighths – make sure
everyone folds the same direction so that all eighths are the same size
Cut 1/8 strips (along fold lines) Share out your strips so that everyone
ends up with 8 strips of eight different colours
Cut strips as directed to match magnets
Uses of fraction strips
Order unit fractions and fractions with the same denominator and explain why they are larger or smaller – Which is bigger? Why?
Order fractions visually using materials, including improper fractions and explain what the numerator and denominator mean. – Make pairs of fractions. Which is bigger?
Which is the bigger fraction?
Many students miss the comparative nature of fractions – the relationship between the numerator and denominator. (Some research suggests that the failure to understand this is a reason why students have difficulty with fractions)
Operational Construct ¼ of 36
– halve and halve again– relationship between times/division
and fractional strategies– ¾ of 36
0.25 of 36
25% of 36
A Teaching Progression for Percentages
Requires high levels of thinking
Decimals (decimal fractions)
Other handouts
Remember the long term goal – improving their algebraic thinking:
One thing you can do to help this every day is to ask questions in class:
Maths is......explaining...
Fraction Teaching Resources Numeracy Folder – Number – Frac-Ratio
– Key Progressions for Fractions, Decimals, Percentages, Rates and Proportions
– A teaching progression for fractions– Intro to Fractions Worksheets– HIBS material– New Numeracy Books– No Nonsense Number Fractions, stages 5-6– NZMaths (DecimalFractionsOfASet,
AddingFractions) Rime 10 Ticks (Pack 4 Level 4 and Pack 5
Level 2)
Activity: In groups of 2 or 3
Create a brief outline for a lesson that gets students to learn without being taught an algorithm
How to convert to (and vice versa)
How to find 4 fractions equivalent to
How to simplify (a) (b)
3
11
3
4
7
2
72
3635
28