Use 125 small cubes to form a 5*5*5 big cube, how many small cubes can a person see at the same time?
用125个小正方体围成一个5*5*5的大正方体，一个人最多能同时看到多少个小正方体．
<gadget id="calculator">5 * 5 * 3</gadget>
<output>75</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">75 - 15</gadget>
<output>60</output>

<result>60</result>