Several Effective Exercises for a Flabby Stomach

Exercise 1. 
Take a deep breath, fully expanding your diaphragm. Count: one, two, three, four, five. Then relax, exhale all of the air through your mouth. Draw your stomach inward, pulling it up as if you want to hide it under your ribs. Hold your breath. Count: one, two, three. Take a breath again, repeating the exercise the same number of times as your age. E.g. If you're 51, do the exercise 51 times.

In the case that you can't do many repetitions at once, do it throughout the day. You can also do it both sitting and standing, insensibly for all the people around. This exercise helps you manage body fat on a belly and it massages your internal organs. 

Exercise Two: An Angry Cat
Stand on your knees and lean on your palms. Inhale as much air as you can through your nose, drawing your stomach under the ribs, arch your back. Bend your head down to your chest. You should mimic an angry cat that met a dog accidentally. It's called the "h-pose". Hold your breath and count to eight; exhale at eight and relax. Return to the starting position. Repeat 3 times.