Two engineering teams are digging a canal. Team A digs 1.4 kilometers a day, and team B digs 1.6 kilometers a day. After 10 days of cooperation, there are still 9 kilometers left. How many kilometers is this canal?
两个工程队挖一条水渠，甲队每天挖1.4千米，乙队每天挖1.6千米，它们合作挖了10天后，还剩9千米．这条水渠有多少千米？
<gadget id="calculator">1.4 + 1.6</gadget>
<output>3</output>

<gadget id="calculator">3 * 10</gadget>
<output>30</output>

<gadget id="calculator">30 + 9</gadget>
<output>39</output>

<result>39</result>