There were 158 boxes of goods in one batch, and after Mr. Li drove them away for 3 times, there were still 68 boxes left. How many boxes does Master Li transport on average each time?
一批货物有158箱，李师傅开车运走了3次后还剩68箱．李师傅平均每次运多少箱？
<gadget id="calculator">158 - 68</gadget>
<output>90</output>

<gadget id="calculator">90 / 3</gadget>
<output>30</output>

<result>30</result>