Teacher Wang bought two reference books. "Primary Mathematics Teaching Guide" is 12.36 yuan, which is 3.28 yuan more expensive than "Mathematics Handbook". How much does Mr. Wang pay?
王老师买了两本参考书．《小学数学教学指导》12.36元，比《数学手册》贵3.28元．王老师应付多少钱？
<gadget id="calculator">12.36 - 3.28</gadget>
<output>9.08</output>

<gadget id="calculator">9.08 + 12.36</gadget>
<output>21.44</output>

<result>21.44</result>