How much should a 12 yr old exercise daily?

# u should excercise 10-13 minutes daily depending on how u feel, # be sure no to push ur self and exercise maybe once every 2 days # don't go crazy and do 300 crunches but doing maybe 30 a night is good # be sure to eat well and don't starve ur self # if u barely eat and then excercise a whole lot then ur body keeps the calories instead of burning them # drink lots of water , water helps flush out extra fats that cause u to weigh an extra pound or 2 # remember weighing ur self without clothes gets ur accurate weight because ur clothes & shoes weigh bout 5 ib. # be strong and stay fit ! # GOOD LUCK!!!!!!!!!!!!!!