Hongye Garment Factory rushed to produce 840 sets of school uniforms for Dongfeng Primary School students. It has been done for 6 days, with an average of 52 sets per day. The rest should be completed within 8 days. How many sets should be made per day on average?
红叶服装厂为东风小学学生赶制840套校服，已经做了6天，平均每天做52套，剩下的要在8天内完成，剩下的平均每天应做多少套？
<gadget id="calculator">52 * 6</gadget>
<output>312</output>

<gadget id="calculator">840 - 312</gadget>
<output>528</output>

<gadget id="calculator">528 / 8</gadget>
<output>66</output>

<result>66</result>