A story book has 70 pages, and I read 20% of it on the first day, how many pages are left?
一本故事书70页，第一天看了20%，还剩下多少页．
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">70 * (4/5)</gadget>
<output>56</output>

<result>56</result>