Try this 20 minutes abs workout every day for a flatter and firmer stomach .
Arms-high partial sit up 3 x 20 reps
Lie on your back, knees bent at 90 degrees, and raise your arms straight overhead, keep them pointing up throughout the exercise. Sit up halfway, then steadily return to the floor.
Russian twists 3 x 20 reps
Sit on the floor in the top position of a sit-up and holding a weight with both hands, extend your arms in front of you. Explosively twist your body to one side and then twist back. Alternate sides.
Leg raises 3 x 15 reps
Lie on the floor and hold onto a bench or the legs of a heavy chair for support. Kepp your legs straight and raise them up until they’re vertical. lower back down, but stop just short of the floor to keep tension on your abs before the next rep.
Flutter kicks 3 x 45 seconds
Lie on your back with your legs straight and arms extend out at your sides. Lift your heels about 6 inches off the floor and rapidly kick your feet up and down in a quick, scissor-like motion.
Plank 3 x As long as you can hold it!!!
Get into pushup position and bend your elbows to lower your forearms to the floor. Hold the position with abs braced.