A super-sized (16x15) puzzle today from veteran constructor, Peter A. Collins. I love the trick today of dropping in the "Palindromic number" (212) and then using the numerals in one of the thematic answers - H2OSBOILINGPOINT, and two non-themers. The inclusion, in the theme clues of a degree symbol and a slash might not have been strictly necessary, but I guess it helped me to solve the puzzle more quickly. In fact, there was kind of a "math-y" feel to a few other clues as well, like 57D: Teaser that may include pluses and minuses (REBUS) and 59D: Summation symbol, in math (SIGMA), and, I suppose, even 21A: Number between cinque and sette (SEI) and 46A: Like 2001 (ODD) (Tricky!), but that's to be expected from a math teacher.
I very much enjoyed 1A: Intelligible (COHERENT), 23A: Exploit (DEED) (which I read with the wrong emphasis for quite some time), 47A: Relative whose name sounds like a city in France (NIECE) (Hah!), and SEMINUDE (73A: Like many classical statues). And who doesn't love A1SAUCE?
Some of the entries may have been a tad OLDSCHOOL, like APOLOGIA (15A: Formal defense), EISNER (52D: Former Disney exec Michael), ANI (20A: Tropical black bird) (Classic!), and BRANDI (54D: Soccer star Chastain), but nothing too musty.
Overall, I enjoyed this one. A fine start to The Turn!