Transcript Leadtcher t4

Lead Teacher Term Four
Fractions
11/12 November 2011
Body Fractions Game
• Arm Span = 1
• One arm = half
• What is a quarter?
• Make one half, three quarters, one, etc
• With a partner three halves
• In a group of four…
Dotty Pairs Game
• You need two sets of cards 1-6 or dice
• The children play in pairs. One child takes dots, the other
takes crosses.
• The players take turns turning over two cards or roll the dice.
The numbers are used to form a fraction e.g 2 and 5 are
turned over - could make two fifths or five halves.
• One fraction is chosen and marked on a 0-6 number line with
the players identifying mark.
• Winner is the person who can get three uninterrupted marks
on the number line.
• If a fraction is already marked on the number line the player
misses that turn.
0
1
2
3
4
5
6
Top and bottom numbers
• What does the bottom number in a fraction
tell us?
• What does the top number in a fraction tell
us?
Top and bottom numbers
• The top number counts
• The bottom number tells what is being
counted.
Fraction Language
Use words first then introduce symbols with care.
e.g. ‘one fifth’ not 1/5
How do you explain the top and bottom numbers?
The number of parts chosen
1
2
The number of parts the whole has been
divided into
The problem with “out of”
1
2 +
2
3
8
6
2
3
3 = 5
x 24 =
“I ate 1 out of my 2
sandwiches, Kate ate 2 out
of her 3 sandwiches so
together we ate 3 out of the
5 sandwiches”!!!!!
2 out of 3 multiplied by 24!
= 8 out of 6 parts!
What connections have you made between
fractions and proportional reasoning?
The language
Importance of building conceptual understanding
(Skemp – Relational vs Instrumental)
Appropriate use of materials
Summary of Fractions Key Ideas
1. Use sets as well as shapes/regions from early on
2. Fraction Language - use words first and introduce symbols
carefully.
3. Go from Part-to-Whole as well as Whole-to-Part
4. Division is the most common context for fractions.
5. Fractions are not always less than 1, push over 1 early.
6. Fractions are numbers as well as operators.
7. Fractions are always relative to the whole.
8. Consider the relationship between ratios and fractions
9. Use addition/skip counting to find fractions of sets then
develop and apply multiplicative thinking –
Fractions are really a context for add/sub and
mult/div strategies
2011
• 349 – Peter Hughes paper Understanding and Extending
Mathematical Thinking. 6 days – 3 Saturdays, in
Whangarei, first Monday of each holiday at Dargaville
Primary
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