A square of colored paper has a circumference of 20 cm. Now use 1 cm2 of small square white paper to cover the colored paper. How many sheets are needed?
一张正方形彩纸周长是20厘米，现用1平方厘米的小正方形白纸铺满这张彩纸，需要多少张．
<gadget id="calculator">20 / 4</gadget>
<output>5</output>

<gadget id="calculator">5 / 1</gadget>
<output>5</output>

<gadget id="calculator">5 * 5</gadget>
<output>25</output>

<result>25</result>