Calculations can be carried out using percentages of shapes and quantities. We can calculate percentage increase and decrease, as well as express a quantity as a percentage of another quantity.

Percent means 'out of one hundred', so \(15\%\) means \(15\) out of one hundred.

\[15\% = \frac{{15}}{{100}} = 0.15\]

Find \(30\% \,of\,\pounds800\)

\[= \frac{{30}}{{100}} \times 800\]

\[= 0.3 \times 800\]

\[= \pounds240\]