The price of a kind of wire is 3.16 yuan per meter. If you buy 15 meters of this wire and pay the salesperson 50 yuan, how much should you get back?
一种电线的价格是每米3.16元，买15米这样的电线，付给售货员50元，应找回多少元？
<gadget id="calculator">3.16 * 15</gadget>
<output>47.4</output>

<gadget id="calculator">50 - 47.4</gadget>
<output>2.6</output>

<result>2.6</result>