Transcript Fractions Powerpoint - Liana Krha

Fraction Revision
Fractions revision
When something is divided into equal parts, each part is
called a fraction.
Which is the numerator?
Which is the denominator?
Numerator: represents the number of parts being
considered
Denominator: represents the total number of
equal parts
Things you should know
The top number of a fraction is the
NUMERATOR
The bottom number of a fraction is the
DENOMINATOR
Fraction
Percentage
Decimal
1/2
50%
0.5
1/4
25%
0.25
3/4
75%
0.75
1/5
20%
0.2
1/10
10%
0.1
1/100
1%
0.01
Equivalent Fractions
• Equivalent fractions means the same as equal
fractions. For example it can be clearly seen below
that the shaded area of each of the circles is exactly
the same.
• Equivalent fractions are obtained by multiplying or
dividing both the numerator and denominator
2/4, ½ and 3/6 look different but these
fractions
are
the
same,
are
Three
They
friends
allall
each
eat
6have
sweets
12they
sweets
Abbie puts hers into 4 piles
EQUIVALENT
Libby puts hers into 2 piles
and eats 2 of them
and eats 1 of them
Abbie has had
2/4
Libby has had
1/2
Chrissy puts hers into 6
piles and eats 3 of them
Chrissy has had
3/6
Are these fractions EQUIVALENT?
Simplify the
fractions
Look for the
biggest number
that goes into the
top and bottom
of the fractions
Divide by the
number
These fractions
are equivalent
8
24
12
36
÷8
1
3
÷12 1
3
Are these fractions EQUIVALENT?
Simplify the
fractions
Look for the
biggest number
that goes into the
top and bottom
of the fractions
Divide by the
number
These fractions
are NOT
equivalent
8
10
12
16
÷2
4
5
÷4
3
4
Are these fractions EQUIVALENT?
Simplify the
fractions
Look for the
biggest number
that goes into the
top and bottom
of the fractions
Divide by the
number
These fractions
are equivalent
9
12
21
28
÷3
3
4
÷7
3
4
What number goes here?
15
20
32
40
÷5
3
4
÷8
4
5
What number goes here?
2
3
1
5
X8
8
24
X9
9
45
Equivalent Fractions
10 multiple choice questions.
Work out your answer then
click to see if you were
right
Which fraction is equivalent to....
1
2
A)
3
9
C)
4
8
B)
2
8
D)
4
10
Which fraction is equivalent to....
1
3
A)
C)
3
9
4
8
B)
4
12
D)
5
20
Which fraction is equivalent to....
1
4
A)
C)
5
16
3
10
B)
7
21
D)
4
16
Which fraction is equivalent to....
1
10
A)
C)
3
30
4
44
B)
4
44
D)
4
44
Which fraction is equivalent to....
3
4
A)
12
20
C)
16
20
B)
18
20
D)
15
20
Which fraction is equivalent to....
2
5
A)
6
25
C)
8
22
B)
6
15
D)
12
35
Which fraction is equivalent to....
5
6
A)
15
24
C)
35
36
B)
D)
30
36
10
18
Which fraction is equivalent to....
4
9
A)
12
54
C)
8
27
B)
16
81
D)
16
36
Which fraction is equivalent to....
5
7
A)
10
21
C)
30
42
B)
35
35
D)
15
28
Which fraction is equivalent to....
9
11
A)
63
77
C)
63
88
B)
27
22
D)
45
44
Simplifying fractions
Many fractions can be reduced down and written in a
simpler form.
To simplify a fraction, both the demoniator and
numerator must be divided by the same number. This
method is often called cancelling down or reducing the
fraction to its lowest terms
Simplifying fractions
• If you got 5 out of 10 correct, what would be a
simpler way or writing it?
Instead of
5
10
we would have
1
2
We have simplified the fractions, by dividing top and
bottom numbers by the same number (in this case 4)
15
3
=
35
7
Divide by 5
24 = 2
36
3
Divide by 12
55
5
=
66
6
Divide by 11
Simplifying fractions
If we pick the biggest number possible to divide
by we only have to simplify once.
We must always check that there are no more
numbers which go into the top and bottom
number
When there are no more numbers which go into
the top and bottom of the fraction, the
fraction is FULLY SIMPLIFIED.
Simplifying Fractions
10 multiple choice
questions
Simplify completely
12
15
A)
3
5
C)
2
5
B)
3
4
D)
4
5
Simplify completely
4
8
A)
1
3
C)
1
2
B)
2
8
D)
1
4
Simplify completely
7
21
A)
3
7
C)
1
8
B)
1
3
D)
1
7
Simplify completely
15
25
A)
C)
3
4
5
6
B)
D)
4
5
3
5
Simplify completely
28
32
A)
C)
7
8
14
16
B)
7
14
D)
4
6
Simplify completely
27
36
A)
5
7
C)
6
8
B)
3
5
D)
3
4
Simplify completely
24
60
A)
3
8
C)
2
7
B)
2
5
D)
1
5
Simplify completely
55
66
A)
8
9
C)
6
7
B)
D)
5
6
4
6
Simplify completely
48
64
A)
C)
3
4
3
5
B)
4
6
D)
2
3
Simplify completely
56
72
A)
1
2
C)
7
9
B)
2
5
D)
6
7
Proper, Improper fractions and mixed
numbers
When you see a fraction with a numerator smaller than a
denominator, it is a PROPER fraction.
When you see a fraction with a large number in front of it,
this is a MIXED NUMBER.
When we have a fraction where the number at the top
(NUMERATOR) is bigger than the number at the bottom
(DENOMINATOR) we have a IMPROPER FRACTION
What type of fractions are these?
22
3
2
35
5
2
3
4
3
2
8
2
1
2
7
2
5
35
Adding and Subtracting
Fractions
Two rulers add three rulers is:
5 rulers
Four pens add five pens is: 9 pens
Two pens add Five rulers is: 7 Pieces of equipment
We can’t do this until we have a name
that describes both groups
When we add fractions we need them to have the same name
(denominator)
Adding and Subtracting
Fractions
2
3 = 5
+
7
7
7
2
4 = 6
+
9
9
9
1
3 = 4
+
11
11
11
Adding and Subtracting
Fractions
2
3 = 5
+
7
7
7
2
4 = 6
+
9
9
9
5
3 = 2
11
11
11
Adding and Subtracting
Fractions
We need to make sure the denominator of both fractions is the
same before we add or subtract
2
3 =
+
5
10
4
3
7
+
=
10
10
10
We need a number in the 5
and 10 times table to
use as our bottom
number- 10?
Adding and Subtracting
Fractions
We need to make sure the denominator of both fractions is the
same before we add or subtract
2
3 =
+
5
6
12
15
27
+
=
30
30
30
We need a number in the 5
and 6 times table to use
as our bottom number30?
a)
b)
c)
d)
e)
7/8
8/12
7/9
7/10
2/3
a)
b)
c)
d)
e)
11/12
7/10
8/15
16/12 or 1 ¼
11/24
a)
b)
c)
d)
e)
1 7/12
1 5/56
29/30
29/52
1 1/10
a)
b)
c)
d)
e)
5/8
5/12
1/3
2/5
1/2
a)
b)
c)
d)
e)
7/20
8/21
23/36
9/22
71/126
Adding and Subtracting Fractions
Click for
answers