The rectangular pillowcase is 75 cm long and 45 cm wide, with lace trimmed around it. How long is the lace?
长方形枕套长75厘米，宽45厘米，四周修花花边，需要多长的花边？
<gadget id="calculator">75 + 45</gadget>
<output>120</output>

<gadget id="calculator">120 * 2</gadget>
<output>240</output>

<result>240</result>