An engineering team repaired a canal with a length of 87 kilometers, and there were 48 kilometers left to be repaired. How many kilometers have been repaired? (column equation solution)
某工程队修一条长87千米的水渠，还剩48千米没有修，已经修了多少千米？(列方程解答)
<gadget id="calculator">87 - 48</gadget>
<output>39</output>

<result>39</result>