A book with 210 sheets is 9.66 cm thick, and another book with the same paper quality is 39.1 cm thick. How many sheets are there?
一本书210张，厚度是9.66厘米，另一本同样纸质的书有39.1厘米厚，有多少张？
<gadget id="calculator">9.66 / 210</gadget>
<output>0.046</output>

<gadget id="calculator">39.1 / 0.046</gadget>
<output>850</output>

<result>850</result>