4 Rules of Fractions
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Transcript of 4 Rules of Fractions
![Page 1: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/1.jpg)
Fractions
This presentation will help you to:• add• subtract• multiply and• divide fractions
![Page 2: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/2.jpg)
Adding fractions
To add fractions together the denominator (the bottom bit) must be the same.
Example
=+8
2
8
1
![Page 3: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/3.jpg)
Adding fractions
To add fractions together the denominator (the bottom bit) must be the same.
Example
=+8
2
8
1=
+8
21
![Page 4: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/4.jpg)
Adding fractions
To add fractions together the denominator (the bottom bit) must be the same.
Example
=+8
2
8
1=
+8
21
8
3
![Page 5: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/5.jpg)
Now try these
Click to see the next slide to reveal the answers.
1. 2.
3. 4.
=+3
1
3
1
=+12
7
12
3=+
7
4
7
2
=+4
1
4
2
![Page 6: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/6.jpg)
Now try these
1. 2.
3. 4.
=+3
1
3
1
=+12
7
12
3=+
7
4
7
2
=+4
1
4
2
3
24
3
7
6
12
10
![Page 7: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/7.jpg)
Subtracting fractions
=−8
2
8
3
To subtract fractions the denominator (the bottom bit) must be the same.
Example
![Page 8: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/8.jpg)
Subtracting fractions
=−8
2
8
3=
−8
23
To subtract fractions the denominator (the bottom bit) must be the same.
Example
![Page 9: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/9.jpg)
Subtracting fractions
=−8
2
8
3=
−8
23
8
1
To subtract fractions the denominator (the bottom bit) must be the same.
Example
![Page 10: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/10.jpg)
Now try these
Click on the next slide to reveal the answers.
1. 2.
3. 4.
=−3
1
3
2
=−12
3
12
7=−7
3
7
4
=−4
1
4
2
![Page 11: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/11.jpg)
Now try these
.
1. 2.
3. 4.
=−3
1
3
2
=−12
3
12
7=−7
3
7
4
=−4
1
4
2
3
14
1
7
1
12
4
![Page 12: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/12.jpg)
Multiplying fractions
To multiply fractions we multiply the tops and multiply the bottoms
Top x Top
Bottom x Bottom
![Page 13: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/13.jpg)
Multiplying fractions
Example
=×3
1
2
1
![Page 14: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/14.jpg)
Multiplying fractions
Example
=×3
1
2
1=
××
32
11
![Page 15: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/15.jpg)
Multiplying fractions
Example
=×3
1
2
1=
××
32
11
6
1
![Page 16: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/16.jpg)
Now try these
Click on the next slide to reveal the answers.
1. 2.
3. 4.
=×3
1
3
1
=×5
3
3
1=×
5
4
4
2
=×4
1
4
2
![Page 17: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/17.jpg)
Now try these
.
1. 2.
3. 4.
=×3
1
3
1
=×5
3
3
1=×
5
4
4
2
=×4
1
4
29
116
2
20
8
15
3
![Page 18: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/18.jpg)
Dividing fractions
Once you know a simple trick, dividing is as easy as multiplying!
• Turn the second fraction upside down
• Change the divide to multiply
• Then multiply!
![Page 19: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/19.jpg)
Dividing fractions
•Turn the second fraction upside down
Example ?=÷31
61
1
3
6
1÷
![Page 20: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/20.jpg)
Dividing fractions
•Turn the second fraction upside down
Example ?=÷31
61
1
3
6
1÷
•Change the divide into a multiply
1
3
6
1×
![Page 21: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/21.jpg)
Dividing fractions
•Turn the second fraction upside down
Example ?=÷31
61
1
3
6
1÷
•Change the divide into a multiply
1
3
6
1×
•Then multiply =××
=×16
31
1
3
6
1
![Page 22: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/22.jpg)
Dividing fractions
•Turn the second fraction upside down
Example ?=÷31
61
1
3
6
1÷
•Change the divide into a multiply
1
3
6
1×
•Then multiply =××
=×16
31
1
3
6
1
6
3
![Page 23: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/23.jpg)
Now try these
Click on the next screen to reveal the answers.
1. 2.
3. 4.
=÷2
1
3
1
=÷5
4
2
1=÷
6
2
4
1
=÷3
2
4
1
![Page 24: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/24.jpg)
Now try these
1. 2.
3. 4.
=÷2
1
3
1
=÷5
4
2
1=÷
6
2
4
1
=÷3
2
4
1
3
28
3
8
6
8
5
![Page 25: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/25.jpg)
Common denominators
To add or subtract fractions together the denominator (the bottom bit) must be the same.
So, sometimes we have to change the bottoms to make them the same.
In “maths-speak” we say we must get common denominators
![Page 26: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/26.jpg)
Common denominators
To get a common denominator we have to:
1. Multiply the bottoms together.
2. Then multiply the top bit by the correct number to get an equivalent fraction
![Page 27: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/27.jpg)
Common denominators
For example ?3
1
2
1=−
![Page 28: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/28.jpg)
Common denominators
For example
1. Multiply the bottoms together
?3
1
2
1=−
632 =×
![Page 29: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/29.jpg)
Common denominators
For example ?3
1
2
1=−
2. Write the two fractions as sixths
6
?
2
1=
6
?
3
1=
![Page 30: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/30.jpg)
Common denominators
For example
?3
1
2
1=−
To get ½ into sixths we have multiplied the bottom (2) by 3. To get an equivalent fraction we need to multiply the top by 3 also
![Page 31: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/31.jpg)
Common denominators
For example
?3
1
2
1=−
To get ½ into sixths we have multiplied the bottom (2) by 3. To get an equivalent fraction we need to multiply the top by 3 also
6
3
6
31
2
1=
×=
![Page 32: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/32.jpg)
Common denominators
For example
?3
1
2
1=−
To get 1/3 into sixths we have multiplied the bottom (3) by 2. To get an equivalent fraction we need to multiply the top by 2 also
![Page 33: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/33.jpg)
Common denominators
For example
?3
1
2
1=−
To get 1/3 into sixths we have multiplied the bottom (3) by 2. To get an equivalent fraction we need to multiply the top by 2 also
6
2
6
21
3
1=
×=
![Page 34: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/34.jpg)
Common denominators
For example
?3
1
2
1=−
We can now rewrite
=−3
1
2
1
![Page 35: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/35.jpg)
Common denominators
For example
?3
1
2
1=−
We can now rewrite
6
2
6
3
3
1
2
1−=−
![Page 36: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/36.jpg)
Common denominators
For example
?3
1
2
1=−
We can now rewrite
6
2
6
3
3
1
2
1−=−
6
23−=
![Page 37: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/37.jpg)
Common denominators
For example
?3
1
2
1=−
We can now rewrite
6
2
6
3
3
1
2
1−=−
6
23−=
6
1=
![Page 38: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/38.jpg)
Common denominators
This is what we have done:
3
1
2
1−
1. Multiply the bottoms
6
?
6
?−=
![Page 39: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/39.jpg)
Common denominators
This is what we have done:
3
1
2
1−
1. Multiply the bottoms
6
?
6
?−=
2.Cross multiply
6
?
6
31−
×=
![Page 40: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/40.jpg)
Common denominators
This is what we have done:
3
1
2
1−
1. Multiply the bottoms
6
?
6
?−=
2.Cross multiply
6
21
6
3 ×−=
6
?
6
31−
×=
![Page 41: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/41.jpg)
Common denominators
This is what we have done:
3
1
2
1−
1. Multiply the bottoms
6
?
6
?−=
2.Cross multiply
6
21
6
3 ×−=
6
?
6
31−
×=
6
2
6
3−=
![Page 42: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/42.jpg)
Now try these
Click on the next slide to reveal the answers.
1. 2.
3. 4.
=+2
1
3
1
=+2
1
5
4=−
6
1
4
3
=+3
2
4
1
24
14
![Page 43: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/43.jpg)
Now try these
1. 2.
3. 4.
=+2
1
3
1
=+2
1
5
4=−
6
1
4
3
=+3
2
4
1
6
512
11
24
1410
3
12
7=
![Page 44: 4 Rules of Fractions](https://reader034.fdocuments.us/reader034/viewer/2022042510/54874a95b47959f10c8b5430/html5/thumbnails/44.jpg)
For further info
Go to:• BBC Bitesize Maths Revision site
by clicking here: