Oh goodness me no! You don't burn that much in a workout. You'd die. :)
Your body burns somewhere around 1500 calories a day just by existing. So your exercise adds to that, say 300 calories of exercise for a total of 1800. Then if you eat at, say, 1300, you've created a 500 calorie deficit today - just right for a pound a week on average.
You don't exercise ALL your food off! Your body burns most of it just being you! :)
Check out these articles for more info:
Explanation of "Burning more calories than you consume": www.sparkpeople.com/community/ask_the_expe
How your recommend range is calculated: www.sparkpeople.com/resource/calorie_calcu