Have there been any major content (not pedagogical) changes in the basic US high school mathematics curriculum since the mid-1990's? More specifically, if I wanted to become a tutor of high school math today as someone who learned his secondary-level math skills back in the 1990's, would a review of my previous curriculum provide a decent foundation, or would there be skills or concepts that young people are learning that I would likely never have heard of?
As a background, I completed US high school mathematics (up through basic Calculus) in the 1990's. Back then, there was a heavy focus on hand-drawing graphs, along with some level of acceptance of black-and-white 8-bit Z80 graphing calculators as an aid to comprehension. I later completed university level coursework (at least through Linear Algebra) in the early 2000's. My understanding is that students nowadays are drawing fewer hand-graphs and using more and more technical modeling technology, but does this primarily represent changes in pedagogy, or are there concepts that high schoolers are learning today that would not have been covered in the 1990's?
I'm not asking about becoming a full classroom teacher (which would obviously require a strong foundation in modern pedagogy). I'm looking for something along the lines of "Oh, nearly every Algebra II class nowadays covers Smooran's Theorem of Transdynamic Coordination, but it was first discovered in 2008 so you probably never studied it.", or something slightly weaker. I'm not asking about general pedagogical changes like online discussion boards or video chat that we really didn't have access to.
Change in pedagogy
- Everyone's submitting assignments online now instead of writing them out by hand. Here's a tutorial you can go through to learn how to type algebraic equations into MathPedagogyPortal2022 XL for Windows. Why did you buy all of those #2 pencils and packs of graph paper? You must be ancient.
- Oh, everything's pretty much the same, except that we don't put a bar across sevens anymore and "subtraction" is now called "subtractification".
Change in content
- The National Council of Teachers of Mathematics rolled out a new curriculum in 2015 centered around the squiggle and ploop operators as fundamental building-blocks of all other mathematical structures. Students now must reduce most equations, graphs, proofs, and even numbers themselves to squiggle and ploop notation to receive full credit, and homework assignments and tests are always expressed in squiggles and ploops rather than with numbers, variables, operators, or equations like they were in your time. The theorems establishing squiggle and ploop are found in a 2008 paper by Smith and Jones (cite) which is now required reading in third grade and must be learned in its entirety in order to advance to fourth grade. You can go to this website (link) to earn your Adult Remedial Certificate in Squiggle and Ploop Math, don't bother applying to be a tutor until you have it!