Teacher Li bought two teaching reference books. One of them is "Mathematics Teaching Guide", the price is 12.56 yuan, and the other is "Mathematics Handbook", the price of "Mathematics Handbook" is 2.5 yuan cheaper than "Mathematics Teaching Guide". How much should Mr. Li pay?
李老师买了两本教学参考书．其中一本是《数学教学指导》，价钱是12.56元，另一本是《数学手册》，《数学手册》的价钱比《数学教学指导》便宜2.5元．李老师应付多少钱？
<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>