Each person eats 210 grams of grain per meal, how many grams of grain did 4 people eat in 3 days?
每人每顿吃粮食210克，4人3天一共吃了多少克粮食．
<gadget id="calculator">210 * 3 * 4 * 3</gadget>
<output>7_560</output>

<result>7_560</result>