Xinmin Village needs to dig an 840-meter-long canal. It has been dug for 5 days, with an average of 80 meters per day. The rest will be dug within 4 days. How many meters are dug per day on average?
新民村要挖一条840米长的水渠，已经挖了5天，平均每天挖80米．剩下的要在4天内挖完，平均每天挖多少米？
<gadget id="calculator">80 * 5</gadget>
<output>400</output>

<gadget id="calculator">840 - 400</gadget>
<output>440</output>

<gadget id="calculator">440 / 4</gadget>
<output>110</output>

<result>110</result>