It is known that a barrel can hold 7 bottles of orange juice, and a bottle can hold 4 cups of orange juice. How many cups of orange juice can be contained in a barrel?
已知一桶能装7瓶橙汁，一瓶能装4杯橙汁，一桶能装多少杯橙汁？
<gadget id="calculator">7 * 4</gadget>
<output>28</output>

<result>28</result>