The road repair team repairs a 450-meter-long road. The first 3 days are 70 meters a day, and the rest are required to repair 80 meters a day. How many days will it take to complete the repair?
修路队修一条长450米的路，前3天每天修70米，剩下的要求每天修80米，还需要多少天才能修完？
<gadget id="calculator">70 * 3</gadget>
<output>210</output>

<gadget id="calculator">450 - 210</gadget>
<output>240</output>

<gadget id="calculator">240 / 80</gadget>
<output>3</output>

<result>3</result>