Li Lin reads a 150-page story book, and has already read (2/3) of the whole book. How many pages are left?
李林看一本150页的故事书，已经看了全书的(2/3)，还剩多少页没有看？
<gadget id="calculator">2 / 3</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">1 - (2/3)</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">150 * (1/3)</gadget>
<output>50</output>

<result>50</result>