Transcript maths fraction workshop

Aims of session
•
•
To explore the language and skills learnt
in Rushen Primary School relating to
fractions.
To show methods of division used in
Rushen Primary School.
Fractions - what are they?
Part of a whole.
1
2
A number written with the top part (the numerator)
telling how many you have.
and the bottom part (the denominator) telling you how
many parts the whole is divided into,
Language of fractions
•
•
Language of fractions is used all around children,
“here’s my half.” “I’ll cut this cake into equal parts
for the four of us.” etc
We would encourage correct use of terms from
early on - not “my half is bigger than yours!”
Simple fractions
Simple fractions are the common fractions
such as
1
1
1
1
1
1
2
3
4
5
8
10
Equivalent fractions
• Equivalent fractions are fractions that are
equal in size but have a different
denominators or numerators.
1
2
=
2
4
There are many more, use of fraction wall.
Mixed Numbers & Improper fractions
Mixed numbers and improper fractions show
values where there are more than one whole
being shown.
Two and a half pieces is
the same as 5
halves.
2
1
2
=
5
2
Changing fractions to a common
denominator
When fractions are to be ordered or added
than they need to have the same denominator
(link to equivalent fractions)
3
1 1
1
7
4
8 2
4
8
becomes 6 1 4
8 8 8
2
8
7
8
8 is the common denominator as all
denominators are in the times table. If this is
not obvious then multiply the denominators to
find a common denominator.
Ordering fractions
To order fractions of the same denominator
we need to look at the numerator.
6
1
4
3
7
8
8
8
8
8
Smallest to largest
1
3
4
6
7
8
8
8
8
8
Ordering fractions
To order fractions with different denominators
we need to convert all fractions to the lowest
common denominator.
3
1 1
1
7
4
8 2
4
8
becomes 6 1 4
8 8 8
2
7
8
8
7
Smallest to largest
1
2 4 6
7
and then 1
1
1
3
8
8 8 8
8
8
4
2
4 8
Ordering
fractions
Finding fractions of an amount or
quantities.
As a fraction is a division of a whole then we
use division to find a fraction of amounts.
Finding a half means dividing by 2 - to make
two equal sized groups.
1
4
÷4
1 ÷ 3
1 ÷ 5
3
5
ie divide by the denominator.
Finding fractions of an amount or
quantities.
To find fractions such 2/3 then we need to find
a third and then multiply this by 2.
2 of 12 = 1
3
3
is 4 x 2 = 8
Finding fractions of an amount or
quantities.
To find fractions such 2/3 then we need to find
a third and then multiply this by 2.
2 of 12 = 1
3
(12 ÷ 3) is 4 then x 2 = 8
3
Divide by denominator and then multiply this by
the numerator.
Methods of Division HTU by U
•
•
Words linked to division - group, divide,
division, divided by, divisible, factor,
share, half, remainder.
Need to know division facts - related to
times tables knowledge.
Formal method
196 ÷ 6
Methods of dividing
HTU by TU
Repeated subtraction
972 ÷ 36
Formal method
972 ÷ 36