Xiao Li reads a book, she reads (1/5) on the first day and (3/5) on the second day. How much is left to see.
小丽看一本书，第一天看了(1/5)，第二天看了(3/5)．还剩下多少没有看．
<gadget id="calculator">1 / 5</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (1/5) - (3/5)</gadget>
<output>1/5 = around 0.2</output>

<result>1/5 = around 0.2</result>