Li Gang bought 20 stamps of 6 cents and 30 stamps of 8 cents. He paid 50 yuan, how much should he get back?
李刚买了20枚6角的邮票和30枚8角的邮票，他付出50元，应找回多少钱？
<gadget id="calculator">6 * 20</gadget>
<output>120</output>

<gadget id="calculator">8 * 30</gadget>
<output>240</output>

<gadget id="calculator">120 + 240</gadget>
<output>360</output>

<gadget id="calculator">360 / 10</gadget>
<output>36</output>

<gadget id="calculator">50 - 36</gadget>
<output>14</output>

<result>14</result>