Xiao Ming buys 2 stamp albums, each at 14.5 yuan, and he pays the salesperson 50 yuan, how much should he get back?
小明买2本集邮册，每本14.5元，他付给售货员50元，应找回多少元？
<gadget id="calculator">14.5 * 2</gadget>
<output>29</output>

<gadget id="calculator">50 - 29</gadget>
<output>21</output>

<result>21</result>