Ahmad NawazIn a used bookstore as a teenager, I stumbled upon a
   "Primary Mathematics Book" - designed for Elementary school. It
   covered grades 1-5 (ages 7-11 pretty much). It was a very slim
   book. Questions, answers, quizes, very straightforward. In an 80
   page book, they covered years of study. The questions were easy
   to understand and it was the SAME stuff I learned in elementary
   school, but ...- understandable. Now, figure this book was in
   the 1920s. Where were these kids in the 1940s? 10 in 1925, 20 in
   1935 - 25 in 1940: Easily member of military, scientists, etc -
   working on some of the complicated things they needed. The
   quantum physicists of the late 40s and 50s? All probably learned
   from... "