How much sit-ups should i do?

im 15, 5'4, 160lbs, plzz helpp

I want to start getting fit, ive done situps before, but not as a routine. Im 17yrs old, how many situps should i do? do i do like 10situps for 10sets or something? or just keep doing situps for 30mins and take a break. also will i lose weight if i just...

i wanna get a flat stomach in a month and ofcourse abs but i donno how many situps and crunches i need to do.. .. is it even possible for me to achieve this or am i kidding myself? & is there a way i can get this without having to starve myself?...

I'd like to lose weight and get a flat stomach in a month's time (i have a huge party to go to on the first of june and want to look nice for it) how many situps would i have to do per day to firstly lose as much weight as possible before that time ...

I have a physical agility test in one week for a police dept. and I must do 35 situps in one minute. I can currently do 35 situps in about 1 minute and 20 secs. I have been concentrating mostly on my running since that is what I had most trouble with...

I am going to enlist in the Marine Corps within the next month as either Infantry or Firefighter. Right now my run time is at about 25:30 for three miles, situps are at about 80 in 2 minutes (do Marines do situps or crunches? what's the difference?)...

I've tried everything. All different kinds of mats, a towel under the mats, a bedsheet under the mats, aquaphor and cetaphil and nothing works. How can you possibly avoid getting fat without starving to death? Only situps can take off a lot of weight...