Parenting is exactly like that; the puzzle is especially analogous when you're outnumbered. The 1-year-old cannot walk but will eat anything he can get his hands on, the 3 year old can fit between the bars on the bridge but does not have the finger strength needed to release the latch on the carseat, the 5 year old can mantle up a 36" ledge and runs at 8 mph but can assist with caring for the 1-year-old for a maximum of 48.6 seconds before one or the other loses focus...

The good news is that after a few years, these safety puzzles become those mathematics problems where the minivan can carry 7 and drives at an average of 40 mph, Suzy can bike to soccer practice at 12mph but only before sunset, Mike's mom is driving south on the freeway at 70 mph and if you drive north on the back roads at 40 mph, the question is which exit should you choose to meet her at so that the crock pot does not overcook dinner before you turn around?