The Weimin Hotel has 840 beds, an increase of 20% compared to before the expansion. How many fewer beds were there before the expansion than after the expansion?
为民旅社有床位840张，比扩建前增加了20%，扩建前比扩建后少多少张床位？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 + (1/5)</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">840 / (6/5)</gadget>
<output>700</output>

<gadget id="calculator">840 - 700</gadget>
<output>140</output>

<result>140</result>