There is a box of chocolates, the total number is less than 30 pieces, and this box of chocolates is divided among 7 children on average, and there are 3 pieces left, how many pieces of chocolates are there at most in this box?
有一盒巧克力，总数不到30粒，把这盒巧克力平均分给7个小朋友，还余下3粒，这盒巧克力最多有多少粒？
<gadget id="calculator">21 + 3</gadget>
<output>24</output>

<result>24</result>