Xinhua Bookstore purchased 600 new books, sold 190 in the morning and 249 in the afternoon, how many books are left unsold?
新华书店购进新书600本，上午卖出190本，下午卖出249本，还剩下多少本没卖出？
<gadget id="calculator">190 + 249</gadget>
<output>439</output>

<gadget id="calculator">600 - 439</gadget>
<output>161</output>

<result>161</result>