There are 87 story books in the class book corner, and the number of science books is twice that of story books. How many books are there in total?
班级图书角有故事书87本，科技书的本数是故事书的2倍，两种书一共有多少本？
<gadget id="calculator">87 * 2</gadget>
<output>174</output>

<gadget id="calculator">174 + 87</gadget>
<output>261</output>

<result>261</result>