Math Tutor

My daughter finished sorting some books, we found three of these books; I had bought one for each of my kid's families, I used this book often when I was helping the kids with their math homework. I think it might have been the Youtube "how-to" for math before YouTube. I wonder if anyone would use a book to learn something like a math formula anymore.  

I think I will call my doctor's helpline tomorrow. My pain is increasing even though I think I am following the doctor's orders perfectly. I admit I looked up my symptoms online and there are some possibilities I am concerned about. Maybe I am expecting too much for 5 days after a hip replacement.