This exercise is great for entire abdominal area and especially for your side abdominals. If you want to make this exercise even more advanced use wrist weights.
Lie flat on your back and overlap your fingers behind your head. Bend your knees about 60 degrees and keep your feet flat on the floor and about shoulder width apart.
Apply up and side motion. Curl up and bring your left shoulder across your body while bringing your right knee in toward your left shoulder at