Students make 25 windmills in one group, 28 in the second group, 31 in the third group, and 20 in the fourth group. How many do each group do on average?
同学们做风车一组做25个，二组做28个，三组做31个，四组做20个，平均每组做几个？
<gadget id="calculator">25 + 28 + 31 + 20</gadget>
<output>104</output>

<gadget id="calculator">104 / 4</gadget>
<output>26</output>

<result>26</result>