The transmission of a bicycle has a front wheel with a diameter of 25 cm and a rear wheel with a diameter of 10 cm. If the rear wheel turns 100 times, how many times does the front wheel turn?
一个自行车的传动装置，前轮的直径是25cm，后轮的直径是10cm．后轮转100圈，前轮要转多少圈？
<gadget id="calculator">3.14 * 10 * 100</gadget>
<output>3_140</output>

<gadget id="calculator">3.14 * 25</gadget>
<output>78.5</output>

<gadget id="calculator">3_140 / 78.5</gadget>
<output>40</output>

<result>40</result>