Teacher Li wants to make an uncovered cuboid book box for the class, which is 9 decimeters long and 5 decimeters wide. If the volume of this bookcase is to reach 270 cubic decimeters (the thickness of the board is not counted), how many square decimeters of wooden boards are needed at least to make such a bookcase?
李老师要为班级做一个无盖的长方体图书箱，长9分米，宽5分米．如果要使这个书箱的容积达到270立方分米(木板的厚度不计)，做这样一个图书箱，至少需要木版多少平方分米？
<gadget id="calculator">9 * 5</gadget>
<output>45</output>

<gadget id="calculator">270 / 45</gadget>
<output>6</output>

<gadget id="calculator">9 * 6</gadget>
<output>54</output>

<gadget id="calculator">5 * 6</gadget>
<output>30</output>

<gadget id="calculator">54 + 30</gadget>
<output>84</output>

<gadget id="calculator">84 * 2</gadget>
<output>168</output>

<gadget id="calculator">168 + 45</gadget>
<output>213</output>

<result>213</result>