Xiaogang read 30 pages in two days. He read the whole book (3/10) on the first day and 12 pages on the second day. How many pages does this book have?
小刚两天看书30页，第一天看了全书的(3/10)，第二天看了12页，这本书共有多少页？
<gadget id="calculator">30 - 12</gadget>
<output>18</output>

<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">18 / (3/10)</gadget>
<output>60</output>

<result>60</result>