malt©2006 maths/fractions slide show : lesson 4 fractions lesson 4 simplifying fractions
TRANSCRIPT
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Fractions Lesson 4Simplifying fractions
MALT©2006 Maths/Fractions Slide Show : Lesson 4
WALT : find an equivalent fraction which uses the
lowest numbers.
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Simplifying is like finding an equivalent fraction.
MALT©2006 Maths/Fractions Slide Show : Lesson 4
For example, let’s think of an equivalent fraction for
……
6
10
MALT©2006 Maths/Fractions Slide Show : Lesson 4
So remember, what ever we do to the top number we must do to the bottom
number.
6
10
MALT©2006 Maths/Fractions Slide Show : Lesson 4
So here’s an equivalent fraction…… let’s multiply top and bottom by 3…..
6
10
times 3
times 3
18
30
MALT©2006 Maths/Fractions Slide Show : Lesson 4
To simplify a fraction we must change it.
6
10
18
30
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Change it to the smallest numbers possible.
6
10
18
30
Oops, this is not using the smallest numbers . . . .
MALT©2006 Maths/Fractions Slide Show : Lesson 4
So let’s try dividing.
6
10
MALT©2006 Maths/Fractions Slide Show : Lesson 4
But by what ?
6
10
MALT©2006 Maths/Fractions Slide Show : Lesson 4
So let’s try dividing.
6
10
Divide by 2
Divide by 2
MALT©2006 Maths/Fractions Slide Show : Lesson 4
So let’s try dividing.
6
10
Divide by 2
Divide by 2
3
5
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Yes. We have simplified this fraction.
6
10
3
5
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Here’s another
8
14
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Chat. Think.
8
14
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Can we divide 8 and 14 by 5?
8
14
NO
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Can we divide 8 and 14 by 7?
8
14
NO
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Can we divide 8 and 14 by 2?
8
14
yes
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Can we divide 8 and 14 by 2?
8
14
divide by 2
divide by 2
47
MALT©2006 Maths/Fractions Slide Show : Lesson 4
And that’s simplifying
8
14
47
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Even when large numbers are involved, you still follow the same rules.
18
36
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Even when large numbers are involved, you still follow the same rules.
18
36
Let’s try dividing by 2
Let’s try dividing by 2
9
18
MALT©2006 Maths/Fractions Slide Show : Lesson 4
But we’re not there yet!
18
36
Let’s try dividing by 2
Let’s try dividing by 2
9
18
We can simplify further.We can make these numbers
smaller
MALT©2006 Maths/Fractions Slide Show : Lesson 4
What can we divide9 and 18
by?
18
36
Let’s try dividing by 2
Let’s try dividing by 2
9
18
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Guess and check . . . .
18
36
Let’s try dividing by 2
Let’s try dividing by 2
9
18
By 4 ?By 5 ?
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Start with the top number itself.
18
36
Let’s try dividing by 2
Let’s try dividing by 2
9
18
Let’s try dividing top and bottomby 9
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Start with the top number itself.
18
36
Let’s try dividing by 2
Let’s try dividing by 2
9
18
Let’s try dividing top and bottomby 9
Let’s try dividing by 9
Let’s try dividing by 9
1
2
MALT©2006 Maths/Fractions Slide Show : Lesson 4
It doesn’t matter how many steps you take.
18
36
Let’s try dividing by 2
Let’s try dividing by 2
9
18
You keep dividing until you can’t divide any more.
Let’s try dividing by 9
Let’s try dividing by 9
1
2
MALT©2006 Maths/fractions Slide Show : Lesson 4
Try these in your jotter
12
27
12
36
24
32
4
16
10
18
54
81
15
35
18
36
6
12
32
48
18
72
10
50
4
12
9
36
16
40
(a)
(o)(n)
(m)
(l)(k)
(j)(i)(h)
(g)
(f)
(e)(d)
(c)(b)
Simplify them
MALT©2006 Maths/fractions Slide Show : Lesson 4
answers
4
9
1
3
3
4
1
4
5
9
2
3
3
7
1
2
1
2
2
3
1
4
1
5
1
3
1
4
2
5
(a)
(o)(n)
(m)
(l)(k)
(j)(i)(h)
(g)
(f)
(e)(d)
(c)(b)
answers
MALT©2006 Maths/Fractions Slide Show : Lesson 4
Fractions Lesson 4Simplifying fractions
End of this lesson