After the expansion of the school cafeteria, it occupies a total area of 420 square meters, and the increased area accounts for 40% of the original area. How many square meters was the original area?
学校食堂扩建后共占地420平方米，增加的面积占原来面积的40%，原来面积是多少平方米？
<gadget id="calculator">40 / 100</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">1 + (2/5)</gadget>
<output>7/5 = around 1.4</output>

<gadget id="calculator">420 / (7/5)</gadget>
<output>300</output>

<result>300</result>