The side length of a square handkerchief is 20 centimeters. It is necessary to embroider lace around it. How many meters is the lace length?
一块正方形的手帕的边长是20厘米，要给它的四周绣上花边，花边长多少米？
<gadget id="calculator">20 * 4</gadget>
<output>80</output>

<gadget id="calculator">80 / 100</gadget>
<output>4/5 = around 0.8</output>

<result>4/5 = around 0.8</result>