I just spent an excruciatingly long time with my 13 yr old. Mind you, the time with him was pleasant. The time trying to remember algebra had the calcium deposits in my brain pouring out my ears. Pushed Alzheimer's back 3 years! (yes, I just screwed up my medical science also but the 13 yr old hasn't gotten there yet).
Moments like this are what make me long to continue a work from home job. I couldn't do this with a regular job. Even if they had a flex schedule that would let me make up the time the opportunity would not have presented itself.