The school spreads 21 cubic meters of yellow sand in a cuboid bunker with a length of 6 meters and a width of 3.5 meters. How thick can it be?
学校把21立方米黄沙铺在一个长6米，宽3.5米的长方体沙坑里，可以铺多厚？
<gadget id="calculator">6 * 3.5</gadget>
<output>21</output>

<gadget id="calculator">21 / 21</gadget>
<output>1</output>

<result>1</result>