The length, width, and height of a cuboid are 5 cm, 4 cm, and 3 cm respectively. If its length increases by a decimeter, its volume will increase by how many cubic decimeters.
一个长方体的长、宽、高分别是5厘米、4厘米、3厘米，如果它的长增加a分米，它的体积就增加多少立方分米．
<gadget id="calculator">4 * 3</gadget>
<output>12</output>

<result>12</result>