Afternoon mother's helper @Chevy Chase DC family

We have four kids ages 14, 13, 11 and 11. Mom works from home and needs someone who can keep the kids on track - getting snacks, playing outside, finishing homework, practicing guitar - and generally out of her hair from 3:15 to 5:30, roughly, Monday through Friday. We are a short bus ride or drive away from George Washington University in the Chevy Chase neighborhood of D.C. (not the Maryland city).