Mr. Wang spent 34.28 yuan to buy mathematics materials and 43.72 yuan to buy Chinese materials. He paid the salesperson 100 yuan. How much should he get back?
王老师买数学资料用了34.28元，买语文资料用了43.72元，他付给售货员100元，应找回多少钱？
<gadget id="calculator">34.28 + 43.72</gadget>
<output>78</output>

<gadget id="calculator">100 - 78</gadget>
<output>22</output>

<result>22</result>