A cuboid fish tank is (7/10) long and (3/5) wide, and contains (21/100) cubic meters of water. How deep is the water?
一个长方体鱼缸长(7/10)、宽(3/5)，里面盛有(21/100)立方米水，水深多少米？
<gadget id="calculator">21 / 100</gadget>
<output>21/100 = around 0.21</output>

<gadget id="calculator">7 / 10</gadget>
<output>7/10 = around 0.7</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(7/10) * (3/5)</gadget>
<output>21/50 = around 0.42</output>

<gadget id="calculator">(21/100) / (21/50)</gadget>
<output>1/2 = around 0.5</output>

<result>1/2 = around 0.5</result>