4B

Equivalent fractions and simplifying

What a fraction means, making equivalent fractions, and simplifying fractions to lowest terms using the highest common factor.

What a fraction means

In $\dfrac{3}{5}$, the denominator $5$ says the whole is cut into $5$ equal parts. The numerator $3$ says how many parts we have.

Equivalent fractions

Equivalent fractions have the same value

Multiplying top and bottom by k changes how the fraction looks, not its value (the line's steepness).

To simplify, divide the top and bottom by their HCF.

Example 1●

Simplify $\dfrac{24}{36}$.

$\dfrac{24 \div 12}{36 \div 12} = \dfrac{2}{3}$
HCF of 24 and 36 is 12.
Example 2●●

Find the missing number: $\dfrac{3}{8} = \dfrac{\square}{56}$.

$8 \times 7 = 56$, so multiply the top by $7$ too.
$3 \times 7 = 21$
Flashcards
Denominator
The bottom number: how many equal parts in the whole.
Simplify a fraction
Divide top and bottom by the HCF.
$dfrac{15}{20}$ simplified
$\dfrac{3}{4}$
Practice
  1. Simplify $\dfrac{24}{36}$.

  2. $\dfrac{3}{8} = \dfrac{\square}{56}$. Find the missing number.

  3. Simplify $\dfrac{15}{20}$.

  4. Which is not equal to $\dfrac{2}{5}$?

  5. $\dfrac{5}{9} = \dfrac{25}{\square}$. Find the missing number.

  6. Simplify $\dfrac{56}{72}$.

  7. What fraction of an hour is $20$ minutes? Simplify.

  8. In $\dfrac{7}{12}$, the numerator is:

More questions

New numbers every time. Keep going until you get five in a row.

Formula sheet