I suspect it hinges on "caring" - if we assume a child aged 0 to 5 needs constant supervision, that is 84 waking hours or so that need to be supervised. If that supervision is caring, then someone could easily spend 50+ hours caring for them even as they do other things.
And you can just walk off when they're asleep? The might wake up. Someone in that age bracket needs 24/7 care, although much of it is merely requires presence.
