Question: ab exercises you can do at the gym?
Answer: 1 Decline plank with foot touch. Reps 10 each side Rest 10sec. Get into a decline plank position, supporting yourself on your forearms with your feet raised on a bench. ... 
2 Seated Russian twist. Reps 12 each side Rest 10sec. ... 
3 Bicycle crunches. Reps 15 each side Rest 10sec. ... 
4 Plank. Time Max Rest 90sec.