When two or more fractions share the same denominator, you can say they have a common denominator.

Explain how to add related unit fractions with a representation or image

Maths

In this unit pupils will explain how to write a fraction in its simplest form when solving addition and subtraction problems and how to add and subtract related fractions. In the future unit pupils will use their fraction sense to fraction addition, subtraction and comparison explaining how to compare pairs of non-related fractions by converting to common denominators and using fraction sense.

In the prior unit pupils used representations to describe and compare two fractions. They explained the relationship within families of equivalent fractions and used their knowledge of common equivalents to compare fractions with decimals. In this unit pupils will explain how to write a fraction in its simplest form when solving addition and subtraction problems. 

Addition and subtraction of fractions

What fraction of the whole shape is shaded?

One-third of a garden patio is covered by a garden bench. Two twelfths of the garden patio is covered by a table. How much of the garden patio is covered?

$$ {4} \over {8}$$ + $$ {1} \over {8}$$ = $$ {5} \over {8}$$

$$ {4} \over {8}$$ + $$ {1} \over {8}$$ = $$ {5} \over {16}$$

$$ {1} \over {8}$$ + $$ {4} \over {8}$$ = $$ {5} \over {8}$$

$$ {1} \over {8}$$ + $$ {4} \over {8}$$ = $$ {5} \over {16}$$

Tick the equations that represent the image.

$$ {6} \over {12}$$ − $$ {3} \over {12}$$ = $$ {3} \over {12}$$

$$ {6} \over {12}$$ − $$ {3} \over {12}$$ = 3

6 − $$ {3} \over {12}$$ = $$ {3} \over {12}$$

$$ {6} \over {12}$$ − 3  = $$ {3} \over {12}$$

Tick the equation that represent the image (the cross indicates it has been subtracted).

Tick the fraction that is the simplest form of $$ {12} \over {14}$$

Tick the options that could represent the sum:    $$ {5} \over {12}$$  + $$ {3} \over {12}$$ 

Tick the options that could represent the difference:    $$ {10} \over {15}$$  − $$ {5} \over {15}$$

Starter Quiz