How many small cubes with a side length of 1 cm are used to form a large cube with a side length of 3 cm?
用棱长为1厘米的小正方体拼成一个棱长为3厘米的大正方体，至少需要多少个这样的小正方体．
<gadget id="calculator">3 * 3 * 3</gadget>
<output>27</output>

<result>27</result>