This variation of the classic exercise for abs is good for beginners.
Lie down on the floor or on a bench with your legs fully extended with your knees slightly bent.
Hold on to the sides of the bench with both hands or just extend them along the body.
As you exhale, slowly raise your legs so that the shins get perpendicular to the floor or a little bit higher.
Pause for 1-2 seconds at the top and as you inhale, slowly return to the starting position.
Don't swing your body and don't jerk up your legs.
Don't put your legs down between the sets, keep them hanging.