Qianjin Village needs to build a (3/4) kilometer long canal. The full length (3/10) was repaired on the first day, the full length (1/4) was repaired on the second day, and the remaining full length was not repaired.
前进村要修一条长(3/4)千米的水渠．第一天修了全长的(3/10)，第二天修了全长的(1/4)，还剩全长的多少没有修．
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (3/10) - (1/4)</gadget>
<output>9/20 = around 0.45</output>

<result>9/20 = around 0.45</result>