The school plans to distribute exercise books to 16 classes, each class has 240 copies, and 800 copies are needed for spare. How many exercise books should schools buy?
学校准备给16个班发练习本，每班240本，还需800本备用．学校应买多少本练习本？
<gadget id="calculator">240 * 16</gadget>
<output>3_840</output>

<gadget id="calculator">3_840 + 800</gadget>
<output>4_640</output>

<result>4_640</result>