The children's boutique store shipped 210 sets of clothing, and 54 sets remained after selling for 4 months. How many sets of clothing are sold each month on average?
儿童精品商场运进210套服装，卖了4个月还剩54套，平均每个月卖了多少套服装？
<gadget id="calculator">210 - 54</gadget>
<output>156</output>

<gadget id="calculator">156 / 4</gadget>
<output>39</output>

<result>39</result>