Put seven circular pieces of paper with an area value of 1 on the table, and the total area covered by them is equal to 4. Prove that there are always two circular pieces of paper whose overlapping area is not less than (1/7).
将七个面积值为1的圆纸片放在桌面上，它们所盖住的总面积值等于4，求证总有两个圆纸片重叠部分的面积不小于(1/7)．
<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<result>1/7 = around 0.142857</result>