5. Fractions

Lesson

Let's review how to identify a fraction using a model.

What fraction of the square is shaded blue?

Worked Solution

Idea summary

When a fraction is represented in an area model:

To find the numerator of the fraction, count the number of parts shaded.

To find the denominator, count the total number of parts.

This video shows how to add fractions using an area model.

In the image below, \dfrac{1}{2} has been shaded red and \dfrac{1}{4} has been shaded blue.

a

Write the addition that describes the image.

Worked Solution

b

What is the total fraction shaded?

Worked Solution

Idea summary

Area models can help us see the parts of fractions that are being added or subtracted.

This video shows how to subtract fractions using an area model.

The image below shows \dfrac{1}{3} of the rectangle shaded.

a

What is the equivalent fraction in fifteenths?

\dfrac{1}{3}=\dfrac{⬚}{15}

Worked Solution

b

We now want to take away \dfrac{4}{15}.

What is the answer to \dfrac{1}{3}-\dfrac{4}{15}?

Worked Solution

Idea summary

Area models can help us see the parts of fractions that are being added or subtracted.

We can also use number lines to add and subtract fractions.

We want to calculate the sum \dfrac{1}{2}+\dfrac{3}{8}.

a

Complete the statement to make an equivalent fraction for \dfrac{1}{2}.

\dfrac{1}{2}=\dfrac{⬚}{8}

Worked Solution

b

Plot \dfrac{4}{8} on the number line.

Worked Solution

c

Choose the image below that represents the addition \dfrac{1}{2}+\dfrac{3}{8}.

A

B

C

D

Worked Solution

Idea summary

We can use area models to change fractions to their equivalent fraction so the denominators are the same.

We can add and subtract fractions by moving right and left on the number line.

Solve problems involving addition and subtraction of fractions with the same or related denominators