Note: 

Exercising alone is not enough. When it comes to fat loss, You got to make sure that you are in a constant caloric-deficit.

The combination of a caloric deficit + resistance training will result in you getting leaner and stronger.

With that said, here are some of the best exercises you can perform in order to develop your core and burn some calories:

1. V-Ups

Instead of lifting your torso off the floor and to the floor, you will suspend your body in the air in this pose making a v shape.

2. Plank

Planks are an ideal exercise for the abdominal muscles exactly because they engage all major core muscle groups including the transverse abdominus, the rectus abdominus, the external oblique muscle, and the glutes. 

3. Leg-Raises

A good ab exercise to strengthen your major abdominal muscles as well as the deep abs.

4. Flutter Kicks

Specifically targets the lower abdominal wall.

5. Seated In&Outs

A challenging all-around exercise.