The water conservancy engineering team dug a canal, dug the full length (1/4) on the first day, dug the rest (3/7) on the second day, and dug 60 meters on the third day. The canal was just dug. How long is the canal?
水利工程队挖了一条水渠，第一天挖了全长的(1/4)，第二天挖了余下的(3/7)，第三天挖了60米，水渠正好挖完，求这条水渠有多长？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">1 - (1/4)</gadget>
<output>3/4 = around 0.75</output>

<gadget id="calculator">3 / 7</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">(3/4) * (3/7)</gadget>
<output>9/28 = around 0.321429</output>

<gadget id="calculator">1 - (1/4) - (9/28)</gadget>
<output>3/7 = around 0.428571</output>

<gadget id="calculator">60 / (3/7)</gadget>
<output>140</output>

<result>140</result>