The number of people in class 21 is more than 20 and less than 30. There are as many groups as there are people in each group. How many children are there in this class?
二1班的人数比20多，比30少．分的组数和每组的人数同样多．这个班有多少个小朋友．
<gadget id="calculator">5 ** 2</gadget>
<output>25</output>

<result>25</result>