A certain bookstore originally sold a batch of "Classroom Exercises", which sold out (1/5) on the first day and (1/6) on the second day. The first day sold 60 more copies than the second day. How many copies of the original "Classroom Exercises" are there in this bookstore? (solution by equation)
某书店原来了一批《课堂练习》，第一天卖出(1/5)，第二天卖出(1/6)．第一天比第二天多卖了60本．这个书店原来的《课堂练习》共有多少本？(用方程解)
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 / 6</gadget>
<output>1/6 = around 0.166667</output>

<gadget id="calculator">(1/5) - (1/6)</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">60 / (1/30)</gadget>
<output>1_800</output>

<result>1_800</result>