If you have reached the level where you can do 1000 sit-ups then your abs will be pretty strong already. More importantly, if you want abs that are visible (i.e. a "six pack") then you will have to have a low level of body fat. Abs, however strong they become, are often hidden by a layer of fat on the stomach. Cardio (running, walking, cycling, etc) or a diet change is required to make abs appear more pronounced. A mantra among bodybuilders: abs are formed in the kitchen, not in the gym.
1000 minutes
1000 years
1000 rears
1000 divided by 80 = 12.5Hrs
about 1000 years
1000 years
1000 years
500-1000 steps
1000
22
1000 years
1000 / 75 = 13.333 hours