A rectangular pillowcase is 3 decimeters long and 2 decimeters wide. If lace is placed around it, how long will the lace be?
一只长方形枕套长3分米，宽2分米，如果在它的四周镶上花边，花边长多少．
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

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

<result>10</result>