Xiaohua reads an extra-curricular book, and reads (3/5) of the whole book, but there are 142 pages left. How many pages does this extracurricular book have?
小华看一本课外书，看了全书的(3/5)，还剩142页没看．这本课外书一共有多少页？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">142 / (2/5)</gadget>
<output>355</output>

<result>355</result>