I do not know everything. Please ignore any air of Know-It-All (because it is entirely unintentional), and be armed with the absolute surety that my answer is sometimes no more brilliant than, "I don't know." Because I am still learning. New ideas still happen, old ideas evolve into new versions of themselves with added information, and occasionally an old idea is thrown out simply because I determine it to be stupid in light of new evidence or perspective.
I hear your questions, and appreciate the questioners because they wish to know and quite possibly have retained a sense of wonder. If I know an answer to what you ask, then I will chime in with an offering. If you ask the answer to 4+2, then I'll respond with "6". If my child asks the same question, I'll tell him or her "Work it out." Should you wish to know the origin of some mighty big word, I'd love to supply the answer, but again the offspring will likely receive only reference to the large, rather worn, red book with what was once "Dictionary" stamped in gold down its spine. Knowledge-based queries offer a bit of a treasure hunt--- although less so than in the days before the big-mouthed internet was readily available.
The writing is on the wall: the children are reaching the sorts of ages where Mom is losing her grip on the title Knower-of-All-Things. The signal for the coming of the end of this age? Our youngest child recently asked, "What do you mean you don't know?! You are a Mom, and Mom's know everything. So, you have to know everything!" *sigh* Not so much, and one can only hope that "I don't know" will inspire a desire to seek out answers... to research a bit as the lovies mature into a realm that involves theories and ideas rather than bodies of fact.
The Mommy Grapevine has it that Moms lose I.Q. points at an alarming rate as their children hit the teen years. (Well, according to the children anyway.) I'm just hanging onto the idea that I will become gradually brighter again once the children are grown. I might even regain potential intelligence sooner if the darlings develop their brains.