A rectangular pillowcase with a length of 50 cm and a width of 30 cm, with lace sewn around it, how many centimeters of lace should be used?
一个长方形枕套，长50厘米、宽30厘米，四周缝上花边，要用多少厘米的花边？
<gadget id="calculator">50 + 30</gadget>
<output>80</output>

<gadget id="calculator">80 * 2</gadget>
<output>160</output>

<result>160</result>