A section of highway is planned to be repaired for 720 meters in 12 days, but the actual repair is 90 meters per day. How many days will it take less than the plan?
一段公路计划12天修720米，实际每天修90米，实际比计划少用多少天？
<gadget id="calculator">720 / 90</gadget>
<output>8</output>

<gadget id="calculator">12 - 8</gadget>
<output>4</output>

<result>4</result>