Answer:
9
Explanation:
The median is the "middle number"
Simply order them least to greatest
3, 6, 7, 9, 12, 12, 28.
1 2 3 4 3 2 1
So 9 is the middle number.
Mode is the most common and most frequent number in an array.
Mean is the average which you can do by adding all the values together and dividing by the number of numbers. (like 1 + 3 + 5 + 7 = 16. 16/4 since there are 4 numbers.)