A shirt costs \(\$40\). In a sale the price is reduced by \(30\%\). Work out the sale price of the shirt.

A reduction of \(30\%\) leaves \(100\%-30\%=70\%\) of the original price, so the sale price can be found in a single multiplication by the decimal multiplier \(0.7\).

The calculation is \(40\times 0.7\) oe [M1], which gives a sale price of \(\$28\) [A1].

The two-step route gives the same result and is often easier without a calculator: \(10\%\) of \(\$40\) is \(\$4\), so \(30\%\) is \(3\times \$4=\$12\), and \(\$40-\$12=\$28\).

A common error is to stop after finding the \(\$12\) reduction and offer that as the sale price. The question asks for the price paid, so the discount must be subtracted from the original amount, or the multiplier \(0.7\) used directly.