According to statistics: Among the 660 cities in my country, there are (3/10) cities with insufficient water supply. Among these cities with insufficient water supply, another (1/3) city is seriously short of water. How many cities are there in my country that are seriously short of water?
据统计：我国660个城市中，有(3/10)的城市供水不足．在这些供水不足的城市中，又有(1/3)的城市严重缺水．我国严重缺水的城市有多少个？
<gadget id="calculator">3 / 10</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">660 * (3/10) * (1/3)</gadget>
<output>66</output>

<result>66</result>