50 pages of paper are about 0.4 cm thick, and how many pages are there in a book with a thickness of 2 cm.
50页纸大约厚0.4厘米，一本2厘米厚的书大约有多少页．
<gadget id="calculator">0.4 / 50</gadget>
<output>0.008</output>

<gadget id="calculator">2 / 0.008</gadget>
<output>250</output>

<result>250</result>