Xiao Ming has a pile of walnuts, on the first day he sold one-seventh of the pile of walnuts; on the second day he sold one-sixth of the remaining walnuts; on the third day he sold one-fifth of the remaining walnuts; On the first day he sold a quarter of the remaining walnuts; on the fifth day he sold a third of the remaining walnuts; on the sixth day he sold one-half of the remaining walnuts. At this time, there are still 30 walnuts left. So, what is the total number of walnuts Xiaoming sold on the first day and the second day?
小明有一堆核桃，第一天他卖了这堆核桃的七分之一；第二天他卖了余下核桃的六分之一；第三天他卖了余下核桃的五分之一；第四天他卖了余下核桃的四分之一；第五天他卖了余下核桃的三分之一；第六天他卖了余下核桃的二分之一．这时还剩下30个核桃，那么，第一天和第二天小明卖的核桃总数是多少个．
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">30 / (1/2)</gadget>
<output>60</output>

<result>60</result>