Qianjin Primary School is going to distribute exercise books to 18 classes, 125 copies per class, and 50 homework books need to be kept as spares. How many exercise books should schools buy?
前进小学准备发练习本，发给18个班，每班125本，还需要留50本作业本作为备用．学校应买多少本练习本？
<gadget id="calculator">18 * 125</gadget>
<output>2_250</output>

<gadget id="calculator">2_250 + 50</gadget>
<output>2_300</output>

<result>2_300</result>