How many push-ups and crunches should I do before it becomes useful.?

Question

I would like to try to get back into shape, but have limited resources (no gym membership, no real exercise equipment).

I've been doing push-ups and crunches so far, and can do about 30 of each in a row. So here's my question:
Should I be looking at this like a stint on a machine in a gym.. like should I be doing 3 sets of each (maybe 30, then 20 twice or something) to get anywhere? Is what I'm doing now going to give any results?

Oh, and just as a curiosity.. do push-up do much for biceps, or more for triceps?

Answer 1

Well if you want to gain muscle, just doin push ups and crunches allows you to build muscle, but if you want to lose fat, you should do enough sets that they help burn more calories than you've gain due to your food intake.

Answer 2

pecs are well used in a push up