Try a cross trainer at the gym.
There are several cardiovascular exercises that can be used to slim the legs. It is best to do the ones that directly use your legs the most such as jogging, power walking, or aerobic classes.
The best exercises for legs are either machines like an elliptical, a Bowflex or just an ordinary set of free weights. With an elliptical you are doing leg-centric cardio, the other two allow for more weight training and strengthening of the legs.
I'm Fat so i dont give one.
In my view cardio is the best exercise to do; in cardio also especially lungs and hamstring are the best choice for legs.
Do exercises that have to do with your legs being apart or do exercise that have to do with the inner thigh
This depends on what muscles you want to exercise. Your legs contains many muscles including quadriceps, and tibialis. There are few exercises that can at the same time exercise them all. Probably one of the only exercises that can do that is swimming, because swimming works on all your muscles.
its not really possible to actually reduce leg size, unless you are overweight. if you have naturally larger legs then there are ways to tone up, like jogging, or cycling. But it wont like minimise your legs. Sorry!
Weslo Ellipticals are used for total body fitness exercises. By doing bicycling exercises with your legs, you are toning and firming the muscles. Your arms can do rowing exercises.
Exercises which incorporate vigorous or heavy lifting with the lower half of one's body are best to build leg muscles. http://www.bodybuilding.com/fun/wotw25.htm includes a list of exercises which can be effective in meeting this goal.
A 10 year old boy should not be a large amount of strength exercises. Weights should be kept to a minimum. The best exercises for a 10 year old are simple exercises like pushups and squats and bicep curls with light weights. These exercises will work most parts your arms and legs. Proper strength training at a gym should not be attempted until you are at least 13-14 as it can cause damage that will become apparent later in life.
There are a number of websites that offer exercises for senior citizens. The article in the related links has some very simple exercises that can help to strengthen the legs and prevent falls.
Squats, lunges, running. These are VERY good for legs, trust me. I work out usaually everyother day and i do all of theses and my legs are getting into shape rather quickly. I suggest doing 10-20 of each on each leg. :)