Find the volume of the big tank, then divide by the volume of one small tank.<br><br>
&bull; Big cube volume = 18&sup3; = 18 × 18 × 18 = 5832 cm&sup3;<br>
&bull; Small cube volume = 9&sup3; = 9 × 9 × 9 = 729 cm&sup3;<br>
&bull; Number of small tanks = 5832 ÷ 729 = 8<br><br>
Final Answer: 8