18. 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!
25. 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
26. 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
30. 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
31. 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
=
×
=
32. 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
33. 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
=
×
=