Dig a vegetable kiln with a length of 6 meters and a width of 3.5 meters. To make the volume of this vegetable kiln 42 cubic meters, how deep should it be dug?
挖一个菜窑，长6米，宽3.5米，要使这个菜窑的容积为42立方米，应挖多深？
<gadget id="calculator">6 * 3.5</gadget>
<output>21</output>

<gadget id="calculator">42 / 21</gadget>
<output>2</output>

<result>2</result>