3,500 calories is equivalent to 1 lb. You burn aprox 100 cals doing jumping jacks in 10 minutes. Translates to ~ 350 minutes/4 hours a week/50 minutes a day. Possible? Maybe. 10 sets of 5 minutes of jumping jacks every day for a week.
Slimmer figur and loose wight. Rather than putting yourself on a strict diet, you should focus on changing your eating habits to achieve weight loss on a long-term basis. Preferably select foods that contain high amounts of vitamins and trace minerals, healthy fats, protein and fibre.