Fractions of quantities II

So far, we've learned that a fraction is part of a whole. In A Part of Something, we learned that the denominator (bottom number) of a fraction tells us how many parts an amount is divided into. For example, $\frac{1}{2}$12​ means the amount is divided into $2$2 equal groups, $\frac{1}{4}$14​ means the amount is divided into $4$4 equal groups and so on.

For example, if I wanted to find $\frac{1}{5}$15​ of $20$20, I could say $20\div5=4$20÷​5=4. This means $\frac{1}{5}\times20=4$15​×20=4.

But what if I need to know what more than one part is worth? Let's start by watching a video.

 

In summary

You can find a fraction of an amount by

• Dividing the total quantity by the denominator, then multiplying the answer by the numerator, OR
• Multiplying the total quantity by the numerator, then dividing the answer by the denominator.

 

Worked Examples

Question 1
 

 

Question 2