To find the MAD, you have to find the mean, or average, of the numbers first.
2+3+5+7+8+8+9=42
42/7=6
Then, you have to find the difference between the average and each data value (in absolute value)
6-2=4
6-3=3
6-5=1
7-6=1
8-6=2
8-6=2
9-6=3
Then, you add up all the differences.
4+3+1+1+2+2+3=16
And then find the mean of that number.
16/7=2 2/7
Or in decimals, this is about 2.285714
