Lan Lan has 7 story books, and Xin Xin has 4 times as many story books as Lan Lan. How many story books do they have together?
兰兰有7本故事书，欣欣的故事书的本数是兰兰的4倍，两人一共有多少本故事书．
<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<gadget id="calculator">28 + 7</gadget>
<output>35</output>

<result>35</result>