Teacher Wang bought two reference books. "Mathematics Teaching Guide" is 12.56 yuan, and "Mathematics Handbook" is 2.5 yuan cheaper than "Mathematics Teaching Guide". How much does Mr. Wang pay?
王老师买了两本参考书．《数学教学指导》12.56元，《数学手册》比《数学教学指导》便宜2.5元．王老师应付多少钱？
<gadget id="calculator">12.56 - 2.5</gadget>
<output>10.06</output>

<gadget id="calculator">10.06 + 12.56</gadget>
<output>22.62</output>

<result>22.62</result>