In other words, you can't do ab exercises in the hopes of reducing belly fat.
That said, it's still important to work your abs, but you're better off concentrating on cardio, strength training and your diet for the best results.
When you do work your abs, treat them like any other muscle group -- challenge them with a few, well-chosen exercises, perform 2 to 3 sets of 10 to 16 reps, and give them a day of rest between workouts. Some of the most effective exercises include:
Don't forget, there are a number of whole body exercises that work your abs while targeting other muscles, which save time and makes your workouts more functional. You can find these challenging exercises in the following core workouts: