Try This 10 min Intense Full-Body CrossFit Workout. it is only 4 moves! but they kill.
Wow- who knew? Healing your "mummy tummy" :-) Diastasis Recti: how to heal from having kids and get your abs back together. I didn't know the separation between your abdominal muscles will constantly cause the "pooch" and crunches could actually worsen the gap. There are exercises here that will help to strengthen your core and make that gap smaller.
After baby (even if baby is now 4 years old). This workout will tap into the deep abdominal muscles that will pull in your waistline like a corset. Do these moves one after another with no rest in between. Then repeat once.