Lie flat on the floor. Your hands can be wherever is most comfortable.
Lift your legs about 6 inches off the floor with your knees slightly bent. This is your starting position.
Use your abs to lift your legs until your toes are pointing to the ceiling. Your lower back will round and come off the floor a bit. Think of this as a reverse crunch motion.
Then slowly lower your legs back down while still keeping your abs tight. If you can, don’t let your feet touch the floor between reps.
