The bicycle factory plans to produce 100 bicycles per day, and the task can be completed on schedule. The actual production is 120 bicycles per day, and the task is completed 8 days ahead of schedule. How many bikes are there in this batch?
自行车厂计划每天生产自行车100辆，可按期完成任务，实际每天生产120辆，结果提前8天完成任务．这批自行车有多少辆？
<gadget id="calculator">100 * 8</gadget>
<output>800</output>

<gadget id="calculator">120 - 100</gadget>
<output>20</output>

<gadget id="calculator">800 / 20</gadget>
<output>40</output>

<gadget id="calculator">120 * 40</gadget>
<output>4_800</output>

<result>4_800</result>