At the beginning of the new semester, the school distributes 240 notebooks to each class, 16 classes have been distributed, and there are still 870 notebooks left. How many books did the school purchase in total?
新学期开始，学校每班发240本记录本，已经发了16个班，还剩870本．学校一共购进多少本？
<gadget id="calculator">240 * 16</gadget>
<output>3_840</output>

<gadget id="calculator">3_840 + 870</gadget>
<output>4_710</output>

<result>4_710</result>