Two cylinders of equal height, the ratio of the radii of the bases is 2:3, the sum of their volumes is 52 cubic decimeters, what is the difference between their volumes in cubic decimeters?
两个等高的圆柱，底面半径之比为2：3，体积之和是52立方分米，它们的体积之差是多少立方分米．
<gadget id="calculator">4 + 9</gadget>
<output>13</output>

<gadget id="calculator">4 / 13</gadget>
<output>4/13 = around 0.307692</output>

<gadget id="calculator">52 * (4/13)</gadget>
<output>16</output>

<gadget id="calculator">52 - 16</gadget>
<output>36</output>

<gadget id="calculator">36 - 16</gadget>
<output>20</output>

<result>20</result>