The experimental primary school has to make 660 sets of school uniforms. It has been done for 5 days, and 60 sets are made every day. After finishing the remaining 4 days, how many sets should be done on average per day?
实验小学要做660套校服，已经做了5天，每天做60套．剩下的4天做完，平均每天要做多少套？
<gadget id="calculator">5 * 60</gadget>
<output>300</output>

<gadget id="calculator">660 - 300</gadget>
<output>360</output>

<gadget id="calculator">360 / 4</gadget>
<output>90</output>

<result>90</result>