The first way is to do 25% off then $4.00 off.
25% of 25 is $6.25.
25 - 6.25 = 18.75
Deduct the $4.00 discount.
18.75 - 4 = $14.75
The second way is $4.00 off then 25% off.
Subtract the $4.00 discount.
25 - 4 = 21
25% of 21 is 5.25.
21 - 5.25 = $15.75
The final cost for the first way is exactly $1 more, or 100 cents.
Hope this helps!