A basketball is 60 yuan, and the price of a volleyball is 85% of that of a basketball. How much is a volleyball cheaper than a basketball?
一个篮球60元，一个排球价钱是篮球的85%，一个排球比篮球便宜多少元？
<gadget id="calculator">85 / 100</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">60 * (17/20)</gadget>
<output>51</output>

<gadget id="calculator">60 - 51</gadget>
<output>9</output>

<result>9</result>