Myth No. 1: I need exercises to work my 'lower abs' and reduce my pot belly.
First, there is no such thing as 'lower abs.' The six-pack you're going for is actually one long muscle, called the rectus abdominis, that extends from below your chest to your pelvis. To work your abs, you should do exercises to target all four muscles: the rectus abdominis, internal and external obliques and the transverse abdominis.
Second, doing crunches will not help you get a 'six-pack' if you have a layer of fat over your abdominal area. In order the see the muscles, you must reduce your body fat. For more information about this and some great ab exercises, check out Flatten Your Abs.