Here is what I got for the first one. MAD=
1/(N)(|x1-xm|+|x2-xm|+..+|xN-xm|)
=1/5(|85-83|+|83-83|+|87-83|+|90-83|+|70-83|)
=1/5(2+0+4+7+13))
=5.2
And for the second one I got, MAD=
1/(N)(|x1-xm|+|x2-xm|+..+|xN-xm|)
=1/5(|75-76|+|74-76|+|68-76|+|83-76|+|80-76|)
=1/5(1+2+8+7+4))
=4.4