Xiaohua read 180 pages of a book, which happened to be the whole book (3/5). How many pages does Xiao Hua have left?
一本书，小华看了180页，刚好是全书的(3/5)．小华还剩多少页没有看？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">180 / (3/5)</gadget>
<output>300</output>

<gadget id="calculator">300 - 180</gadget>
<output>120</output>

<result>120</result>