There are many, many ways to work out abs.
But getting to a gym or getting a personal trainer, isn't always an option.
Here are some exercises that you can do to get great abs right in your own home, without any special equipment.
1.
Crunches Lie on your back, hands crossed over your chest.
Bend your knees at about a 45-degree angle, and keep your legs slightly apart.
Curl your upper torso toward your knees, keep lifting as high as you can, but don't lift your lower back.
Hold for a second.
Lower slowly, and start again.
2.
Crossover Crunches This crunch also works the obliques, which are the side muscles that help shore up your back.
Lie in the same position as the crunch.
Proceed as for the crunch, but instead of pausing at the top, twist toward your left knee.
Hold for a second, then lower again.
Repeat, but this time twist toward your right knee.
3.
Raised-Leg Crunches Lie on your back with your knees bent and your lower legs up on a bench or chair.
Your thighs should be perpendicular to the floor, and your hands folded across your chest.
Pull your torso toward your knees, lifting your shoulders and shoulder blades off the floor.
Hold for a second, then lower.
Repeat.
4.
Frog-Leg Crunches Lie flat with your knees spread and the soles of your feet together.
Your knees should be as close to the floor as comfortable.
Fold your hands across your chest.
Lift your shoulder blades and upper back off of the floor, curling your pelvis up and in.
Don't lift your lower back off the floor.
Hold for a second, then lower to the starting position.
Repeat.
5.
Hanging Single-Knee Raises Hang from a chin-up bar with your palms facing out and your hands shoulder-width apart, with feet slightly touching the floor.
Raise your right knee toward your left shoulder as far as you can.
Thrust your pelvis forward to help, but don't rock.
Hold for a second, then lower and repeat with your left leg.
6.
Hanging Knee Raise Crossovers Hang in the same position as the last exercises.
Keeping your legs together, lift your knees toward your left shoulder as high as you can.
Thrust your pelvis forward, but don't sway for momentum.
Hold for a second, lower and repeat on your right side.
7.
Vacuums Sit kneeling, with your feet crossed behind you and your hands on your hips.
Keep your upper body upright.
Breathe out, then immediately suck your stomach up and in as far as it will go.
Hold for five seconds.
You can also do this standing.
8.
Raised-Leg Knee-Ins Lie on the floor.
Place your hands palm down on the floor just next to, and slightly under, your butt.
Press the small of your back against the floor and extend your legs about three inches above the floor.
Lift your left knee, keeping your right leg hovering above the floor.
Hold, then straighten your leg again and repeat with the other leg.
9.
V-Spread Toe Touches Lie on your back, and put your legs in an upright "V".
Keep your legs loose, and reach up.
Using your shoulders, reach for your right foot, while tensing your abs.
Hold for a second, then slowly lower your arms.
Repeat for the other side.
With all of these ways to work out abs, you'll be on your way to a killer set in no time.