Having lived in Argentina, I can confirm that this is indeed the case! There is also a version called terere in which cold fruit juice is substituted for hot water.
I'm not convinced this does logically follow. There is a view point that God is the source of math only in the sense that God created humanity with the limited capacity for understanding the world around them and one way this capacity has manifested is through the development of Mathematics.
Why does math work so well? Well math is pretty great but I don't think it is magical. There have been thousands of years of slow mathematical advances to get us to where we are now.
I work in applied mathematics and specifically in CFD. This may make me not a "true mathematician" to some of the mathematical community. In fluid dynamics nearly everything is an approximate solution to an imperfect model. In fact, there are whole branches of mathematics dealing with trying to figure out exactly how imperfect models are. "Perfect math" has limited applicability, and only perfectly reflects reality in contrived situations. For example, linear algebra works amazingly well in the contrived environment of a computer, but if you want to perfectly model the electron flow that is involved in that computation one must necessarily use an imperfect approximation.
As a mathematician and a believer in God, I get uncomfortable when people start attributing math to God. I see math as being very much a construct of the human psyche and as astounding as it is, there are enormous gaps between mathematical models and physical observations. So in my mind math is to reality as human is to Divine.
I had a friend in high school who's father survived a skydiving accident "breaking every bone in his body." What made the biggest impression on me was that not only did he have to recover physically, but he had to deal with inability to work and medical bills leading to bankruptcy and a failed business. It may have been the first time in my life I thought about this kind of consequences.
1) We continue to need new textbooks: Despite relative little change in core materials for subjects like Calculus, there is a need for adaptation of texts to include current applications and methods.
2) The best use of interactive media to complement and enhance learning is yet to be determined.
3) The worst crime of textbook companies is lack of innovation.
I love audiobooks, and have discovered the wonderful wispersync feature to seamlessly pick up my kindle or audible audiobook, which ever is most convenient. I highly recommend the Aubrey/Maturin series read by Patrick Tull. Currently listening to The Magician's Land by Lev Grossman.
This book helped me to visualize Krylov space methods better than any other resource I have seen. It got me through my numerical analysis qualifying exam. I do agree that the last chapters are lacking in depth. I also recommend his book "Pseudo-spectral Methods in Matlab" for a thorough and very visual look at things like Gibb's phenomenon and spectral convergence.
My wife is from a small town in Mexico where there has been a recent surge in violence and kidnappings. Her family is there and we go visit once a year or so as we can. Last time I was there there was a couple of moments that made realize I was just waiting for something terrible to happen. I worry I (as the American) am painting a target on my wife's family. Every time they call unexpectedly I fear for the worst. Right now, I'm not sure if we will go this year.
Oh the dreaded "details left as an exercise." Personally, if I can't fill in details readily myself, I use Google or "just take there word for it" and hope it doesn't bite me later.