When the denominator of one fraction is a multiple of the denominator of another fraction, we can say these fractions are related fractions.

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

Explain how to add related unit fractions without 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

they have the same number for the numerator.

they have the same number for the denominator.

they have the same numerator and denominator.

one has a denominator that is a multiple of the other fraction’s denominator.

Fractions can be called ‘related fractions’ if:

Fractions have a common denominator when:

Tick the ‘related fractions’ of $$ {1} \over {6}$$

Tick the statements that are true: The sum of $$ {1} \over {4}$$ + $$ {1} \over {12}$$ will be:

What number have the numerator and denominator been multiplied by to create a related fraction? {{ }}

Tick the correct answer. $$ {1} \over {5}$$ + $$ {3} \over {20}$$ = ___

Tick the fractions in their simplest form

Tick the sum in its simplest form. $$ {5} \over {8}$$ + $$ {2} \over {8}$$ =

What fraction of the whole shape is shaded?

Tick the difference in its simplest form.    $$ {18} \over {6}$$ − $$ {4} \over {6}$$

Starter Quiz