A piece of tablecloth with a side length of 10dm should be embroidered with lace around it. What is the length of the lace in meters?
一块边长是10dm的桌布，要在它的四周绣上花边，花边的长是多少米．
<gadget id="calculator">4 / 10</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">10 * (2/5)</gadget>
<output>4</output>

<result>4</result>