How do i get the exercise part on mfp to deduct my calories for the entries i put in?

Yes, it's a bit annoying because actually strength exercise does have caloric value, especially when you do legs: heart pumping and sweating profusely for 1 hour works your heart for sure! Look here at the bottom of the table:
http://www.nutribase.com/exercala.htm

You can log the amount of time for "strength training" under the Cardiovascular section to get an estimate for Calories burned. You can use the Strength Training section to log sets, reps, and weights, but that section does not account for the amount of time or Calories burned.

Add "Strength training (weight lifting, weight training)" to Cardiovascular to get estimated Calories Burned added to your Diary. Please note that the Calories burned for Cardiovascular exercises provided by MFP are based on published metabolic equivalent of tasks (METs), which are estimates for a general population and may differ for you as an individual. If desired, add individual strength training exercises, such as "Biceps Curl," to Strength Training to have a log of sets, reps, and weights as individual exercises.

Please see these articles in the list of articles on this topic in the MFP Help pages...
myfitnesspal.desk.com/customer/portal/articles/11170-why-don-t-you-calculate-calories-burned-for-strength-training-
myfitnesspal.desk.com/customer/portal/topics/455842-exercise-diary-and-exercise-database/articles