 # Fractions of Quantities

Lesson

In A Part of Something, and Multiple Parts of Something we began our journey into understanding fractions of quantities.  We looked at unit fractions and the connection with division, and then we moved to looking at non unit fractions of quantities.  Remember how we did these?

#### Example

Find:$\frac{3}{4}$34 of $24$24

Think:  What is $\frac{1}{4}$14 of $24$24?

Do:  $\frac{1}{4}$14 of $24$24 is $6$6 (remember we divide $24$24 by $4$4).

What we really want is $3$3 of the quarters, so $3\times6=18$3×6=18

$\frac{3}{4}$34 of $24=18$24=18

You may be pleased to know that we do not have any more new methods to learn here -> we just need to practice working with more difficult fractions, larger numbers or more worded type practical questions.

#### Worked Examples

##### QUESTION 1

Find $\frac{3}{100}$3100 of $1600$1600.

##### QUESTION 2

What is $\frac{9}{10}$910 of $150$150 kilometres?

##### QUESTION 3

Christa is making a cake and is adjusting the recipe. The recipe says it will serve $5$5 people. Christa needs to serve $4$4 people.

1. What fraction of each ingredient listed on the recipe will Christa need to use? Give your answer in simplest form.

2. The original recipe asked for $\frac{5}{2}$52 cups of flour. How much flour should Christa use?

3. The original recipe asked for $\frac{5}{16}$516 cups of coconut. How much coconut should Christa use?

### Outcomes

#### NA5-3

Understand operations on fractions, decimals, percentages, and integers