Xiao Ming spent 15.5 yuan to buy a pen and 24.6 yuan to buy a book. How much did Xiao Ming spend in total?
小明买笔用了15.5元，买书用了24.6元，小明一共用了多少钱．
<gadget id="calculator">15.5 + 24.6</gadget>
<output>40.1</output>

<result>40.1</result>