The fruit shop brings in 21 more baskets of lychees than bayberry, and the number of baskets of litchi is 4 times that of bayberry. How many baskets of lychees does the fruit shop bring in?
水果店运进荔枝比杨梅多21筐，荔枝的筐数是杨梅的4倍．水果店运进荔枝多少筐？
<gadget id="calculator">4 - 1</gadget>
<output>3</output>

<gadget id="calculator">21 / 3</gadget>
<output>7</output>

<gadget id="calculator">7 * 3</gadget>
<output>21</output>

<result>21</result>