Participating in the 2009 National Day military parade included foot formations, equipment formations and air echelon formations. It is known that the foot formation is 4 fewer than the equipment formation (3/5); the equipment formation has 30; the air echelon is less than the equipment formation (3/5). How many foot formations, equipment formations and air echelon formations are there?
参加2009年国庆阅兵的有徒步方队、装备方队和空中梯队．已知徒步方队比装备方队的(3/5)少4个；装备方队有30个；空中梯队比装备方队少(3/5)．徒步方队、装备方队和空中梯队共有多少个？
<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">30 * (3/5)</gadget>
<output>18</output>

<gadget id="calculator">18 - 4</gadget>
<output>14</output>

<gadget id="calculator">30 - 18</gadget>
<output>12</output>

<gadget id="calculator">30 + 14 + 12</gadget>
<output>56</output>

<result>56</result>