Me with (mad) mean absolute deviation. i don't get !

To Solve MAD or the mean absolute deviation what you need to do is get the Mean so lets say  you have the numbers 20,35,18,34,60,82,10, and 29 add them up to get 228. next divide by the amount of numbers 228/8 = 36 now to get the mean absolute deviation get the difference of each number, but some will be negative so we will turn them to positive Like so.
20-36=-16 turn to positive 16
36-35=1
36-18=18
36-34=2
60-34=24
82-34=46
36-10=26
and 36-29=7
you add up these numbers to get 140 then divide them by the numbers 140/8=17.5
so 17.5 is your mean absolute deviation.

After 7 minutes the oven will be 205 degrees