A hare and a tortoise race on a 100-meter circular track. They start from the same place at the same time, every time the tortoise crawls 5 meters, the rabbit surpasses it by one circle. How many laps did the rabbit run when the tortoise completed one lap?
兔子和乌龟在100米的环形跑道上赛跑．它们从同一地点同时出发，乌龟每爬行5米，兔子超过它一圈．当乌龟爬完一圈时，兔子跑了多少圈．
<gadget id="calculator">100 / 5</gadget>
<output>20</output>

<gadget id="calculator">100 + 5</gadget>
<output>105</output>

<gadget id="calculator">105 / 100</gadget>
<output>21/20 = around 1.05</output>

<gadget id="calculator">20 * (21/20)</gadget>
<output>21</output>

<result>21</result>