There are 1,800 table tennis balls, each of which is packed in a tube of 6, and every box of 20 tubes is packed. How many boxes do these table tennis balls need to pack?
有1800个乒乓球，每6个装一筒，每20筒装一箱，这些乒乓球需要装多少箱？
<gadget id="calculator">6 * 20</gadget>
<output>120</output>

<gadget id="calculator">1_800 / 120</gadget>
<output>15</output>

<result>15</result>