Fraction bars (2,3,4,5) (Yr 3)

Lesson

Representing fractions

We use fractions when we are dividing something evenly:

• Fraction bars give a visual representation
• We divide the bar into equal parts
• The denominator (the bottom number of the fraction) shows how many equal parts
• We shade parts to show the value we are representing
• The numerator (the top number of the fraction) shows how many parts to shade

Halves

If we divide something into two equal parts, each part would be $\frac{1}{2}$12 (one half) of the whole. $\frac{2}{2}$22 is two halves and they make one whole.

The fraction bar above is representing $\frac{1}{2}$12 as there are two parts and one of them is shaded.

Thirds

When we divide the fraction bar into three equal parts we name this fraction thirds. If we want to show $\frac{2}{3}$23 on a fraction bar, we would then shade two of them.

The fraction represented at the red box in the picture is $\frac{2}{3}$23 as there are three equal parts and two of them are shaded.

Quarters

Quarters is the name we give fractions when we divide the whole into four equal parts. When representing this in symbols we put the number of parts as the bottom number of the fraction (denominator) and the number of parts shaded as the top number in the fraction (numerator). Let's look at a picture that shows $\frac{2}{4}$24.

Each part in the picture above is one quarter or $\frac{1}{4}$14. There are two parts shaded so the fraction bar is representing $\frac{2}{4}$24.

Fifths

When we divide into five equal parts the name of the fraction is fifths. When we want to represent a certain number of fifths we can shade the number of fifths we want to show. The picture below is representing fifths.

You can shade in three parts to represent $\frac{3}{5}$35 or three fifths, or four parts to represent $\frac{4}{5}$45. Remember, each part is $\frac{1}{5}$15 and we can shade in as many as we need to represent a fraction of the whole.

Remember!

The number of equal parts the whole is divided into is the denominator (bottom number). The numerator (top number) is how many parts, so shows the value of the fraction.

Now try some example questions for yourself.

Worked examples

question 1

Here is a fraction bar.

1. This fraction bar has $\editable{}$ equal parts.

2. Each part is $\frac{\editable{}}{\editable{}}$ of the whole.

question 2

Which of the following shows $\frac{1}{2}$12 on the fraction bar?

1. A
B
C
D
A
B
C
D

question 3

We are going to represent the fraction $\frac{1}{4}$14 on a fraction bar diagram.

1. How many parts do we divide the bar up into?

We divide the bar into $\editable{}$ equal sized parts.

2. Here is the fraction bar split into four parts.

Which of the following represents $\frac{1}{4}$14 on the fraction bar?

A
B
C
D
A
B
C
D
3. How big is the orange part?

The orange part is $\frac{\editable{}}{\editable{}}$ of the whole.

Outcomes

NA2-5

Know simple fractions in everyday use