pencil is 0.5 yuan, and a ballpoint pen is 3.2 yuan. How much is a pencil cheaper than a ballpoint pen?
一支铅笔0.5元，一支圆珠笔3.2元，铅笔比圆珠笔便宜多少元．
<gadget id="calculator">3.2 - 0.5</gadget>
<output>2.7</output>

<result>2.7</result>