Simple answer to this question is NO.
You can’t actually remove belly fat alone just by doing crunches, leg raises, plank and other abdomen exercises. You can burn belly fats only by burning fats from all over the body.
You would have heard of the Spot Reduction : reducing fat from a particular spot.
Spot reduction refers to the fallacy that fat can be targeted for reduction from a specific area of the body and that it can be achieved through exercise of specific muscles in the desired area, such as exercising the abdominal muscles in an effort to lose weight in or around one’s midsection. Advertisers exploit this concept when advertising exercise-related products. However, many fitness experts believe, and studies have shown, that it is not possible to reduce fat in one area by exercising that body part alone. Instead, fat is lost from the entire body as a result of diet and regular exercise. Muscle growth in the abdominal region does not reduce fat in that region. Instead, being on a caloric deficit is recommended for reducing abdominal fat.
You have to burn fats from all over your body and not from a particular spot. Doing cardio exercises will help to burn fats from all over the body and then slowly start with exercises like crunches, leg raises, plank etc side by side. After few weeks, you’ll really feel the change which will motivate you to go ahead. But reaching that point of change is the most difficult part which really requires lot of commitment and hard work.
Summary : Do Extreme cardio exercises like Running/Swimming 3-4 times a week which will help to burn body fat easily. And then slowly start with abdomen exercises side by side. Remember there is no shortcut to Success.