Calculations involving percentages of quantities. Working with increases and decreases as well as expressing a quantity as a percentage of another quantity.
Part ofMathsNumeracy
You need to be able to use basic skills of working with percentages for many different calculations.
Most of these questions will be in a real life context.
Per cent means 'out of one hundred', so \(15\%\) means \(15\) out of \(100\).
\(15\% = \frac{{15}}{{100}}\)
Calculate \(15\%\) of \(\pounds200\)
\(\frac{15}{100}\times 200= \pounds30\)
Now try the example question below.
Find \(30\%\) of \(\pounds800\).
\(30\% \,of\,\pounds800\)
=\(\frac{30}{100}\times 800\)
\(= \pounds240\)
Find \(17\%\) of \(340kg\)
\(17\%\) of \(340kg\)
= \(\frac{17}{100}\times 340\)
A way of doing this on a calculator is \(340 \div 100 \times 17\).
\(=57.8kg\)
Find \(15\%\) of \(260cm\)
\(15\%\) of \(260cm\)
= \(\frac{15}{100}\times 260\)
One way of doing this on a calculator is \(260\div 100\times 15\).
\(=39cm\)
