There are 100 copies of a new book in Xinhua Bookstore, 62 copies are sold in the morning, and 29 copies are sold in the afternoon. How many copies are left?
新华书店的一种新书有100本，上午卖出62本，下午卖出29本，还剩下多少本？
<gadget id="calculator">62 + 29</gadget>
<output>91</output>

<gadget id="calculator">100 - 91</gadget>
<output>9</output>

<result>9</result>