The original price of a story book is 24.8 yuan. Now it is sold at 40% off the original price. How much is it cheaper?
一本故事书原价24.8元．现在按原价的六折出售，便宜了多少元？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">24.8 * (2/5)</gadget>
<output>9.92</output>

<result>9.92</result>