Hi everyone!
Here is some guidance for today’s maths lesson – comparing fractions.
When comparing fractions with different denominators (the number on the bottom), you first need to make them the same – this is called finding the common denominator.
Let’s look at this example:
Compare 7/8 with 3/4
8 and 4 are our denominators – they are different. We need to make them the same.
8 is going to be our common denominator because we cant divide 7 into a whole number.
In order to make our fraction of 3/4 have a denominator of 8, we need to multiply the 4 (current denominator) by 2.
3/4 becomes 3/8
However, we must remember, whatever we do to the bottom, we do to the top.
3/4 becomes 6/8.
Now we can compare our fractions: 7/8 and 6/8
Which is bigger? Well 7/8 is bigger than 6/8 because it is a larger fraction.
Remember, 6/8 is the same as 3/4 – it is just written in a different way for the purpose of comparing.
So, we can say: 7/8 is bigger than 3/4 by 1/8.
How about if we are comparing 2/3 and 3/4.
Well, 3 doesn’t go into 4, so our common denominator will have to be a number that is a multiple of both 3 and 4.
12!
Let’s make our fractions have a common denominator of 12.
2/3 becomes 8/12 (multiplied the bottom by 4 so we multiply the top by 4)
3/4 becomes 9/12 (multiplied the bottom by 3 so we multiply the top by 3)
Which is bigger?
3/4 is bigger than 2/3 by 1/12!
I hope this helps.
Any further questions, please don’t hesitate to ask.