A small cardboard box whose length, width and height are 40cm, 30cm and 20cm respectively, stick a circle of tape on all the edges, at least how much tape is needed.
一个长、宽、高分别为40cm、30cm、20cm的小纸箱，在所有的棱上粘上一圈胶带，至少要多少胶带．
<gadget id="calculator">40 + 30 + 20</gadget>
<output>90</output>

<gadget id="calculator">4 / 100</gadget>
<output>1/25 = around 0.04</output>

<gadget id="calculator">90 * (1/25)</gadget>
<output>18/5 = around 3.6</output>

<result>18/5 = around 3.6</result>