The side length of large tiles is 30 cm, and the side length of small tiles is 20 cm. If the floor of a room is paved with large tiles, 72 tiles are exactly covered. If it is changed to pave the floor with small tiles, how many tiles are needed?
大瓷砖的边长是30厘米，小瓷砖的边长是20厘米，一间房的地面如果用大瓷砖铺，72块正好铺满．如果改成用小瓷砖铺地，需要多少块？
<gadget id="calculator">30 * 30 * 72</gadget>
<output>64_800</output>

<gadget id="calculator">20 * 20</gadget>
<output>400</output>

<gadget id="calculator">64_800 / 400</gadget>
<output>162</output>

<result>162</result>