The children's clothing factory needs to produce 500 sets of school uniforms, 300 sets have been produced, and the rest will be produced in 4 days. How many sets are produced on average per day?
儿童服装厂要生产500套校服，已经生产了300套，剩下的要4天生产完，平均每天生产多少套？
<gadget id="calculator">500 - 300</gadget>
<output>200</output>

<gadget id="calculator">200 / 4</gadget>
<output>50</output>

<result>50</result>