Six days before the start of school, Xiao Ming has not started to do his winter vacation math homework, but Xiaoqiang has already completed 60 questions, and both of them have completed their winter vacation math homework at the beginning of school. During these 6 days, Xiaoming did three times as many winter vacation math homework as Xiaoqiang. How many winter vacation math homework questions does he do on average every day?
开学前6天，小明还没有开始做寒假数学作业，而小强已经完成60道题，开学时两人都完成了寒假数学作业．在这6天中，小明做的寒假数学作业数目是小强的3倍，他平均每天做多少道寒假数学作业题目？
<gadget id="calculator">3 - 1</gadget>
<output>2</output>

<gadget id="calculator">60 / 2</gadget>
<output>30</output>

<gadget id="calculator">30 + 60</gadget>
<output>90</output>

<gadget id="calculator">90 / 6</gadget>
<output>15</output>

<result>15</result>