It is planned to build 50 kilometers of roads, 35 kilometers have been repaired, and how much is left to be repaired.
计划修50千米公路，已修35千米，还剩多少没修．
<gadget id="calculator">50 - 35</gadget>
<output>15</output>

<gadget id="calculator">15 / 50</gadget>
<output>3/10 = around 0.3</output>

<result>3/10 = around 0.3</result>