The square tablecloth is 100 centimeters long, and it needs to be surrounded by lace. How long is the lace?
正方形桌布长100厘米，要在四周围上花边，花边长多少米？
<gadget id="calculator">100 * 4</gadget>
<output>400</output>

<gadget id="calculator">400 / 100</gadget>
<output>4</output>

<result>4</result>