Will 20-40 crunches a night do anything?

I'm not looking for a six pack or anything, I just want to flatten my tummy. I do 10-20 minutes of cardio 5 days a week and I eat very healthy. I have a lot of fruits and veggies during the day and lean proteins. My stomach isn't big or anything, I just want it to be flatter. Will doing 20-40 crunches a night help?..I know it will probably take longer but still.