How much cardboard is needed to make a cuboid cardboard box with a length of 7 decimeters and a width and height of 2 decimeters? 【Joints not counted】.
做一个长为7分米，宽和高都是2分米的长方体硬纸盒，需要多少硬纸板？【接头处不计】．
<gadget id="calculator">14 + 14 + 4</gadget>
<output>32</output>

<gadget id="calculator">32 * 2</gadget>
<output>64</output>

<result>64</result>