How many calories do I need to burn a day to lose 2 lbs a week?

I'm 5'10 and weigh about 145 lbs. I want to get down to 135lbs. I'm not sure how many calories I burn a day just going thru the motions of day to day tasks. I have also been trying to run/walk 30 mins at least 3 days a week.

I'm not sure how many calories I should be consuming or how many calories I need to burn to reach my goal.

Thanks!