Perhaps a clarification of “standard sequence” could be made.
First, some shorthand terminology:
+0: “normal” college prep math sequence: algebra 1* in 9th grade, precalculus/trigonometry in 12th grade
+1: accelerated by 1 year, algebra 1* in 8th grade, precalculus/trigonometry in 11th grade and calculus in 12th grade
+2: accelerated by 2 years, algebra 1* in 7th grade precalculus/trigonometry in 10th grade and calculus BC in 11th grade
+2-1: accelerated by 2 years through precalculus/trigonometry in 10th grade, but then calculus over two years in 11th and 12 grades
*Or integrated math 1 for schools that have integrated math 1/2/3 instead of algebra 1, geometry, algebra 2.
A “standard sequence” would mean that:
a. The middle school offers the needed high school level math courses (e.g. algebra 1 in a +1 situation, algebra 1 and geometry in a +2 situation).
b. The high school offers the needed college level math courses, or students can conveniently take the needed courses at a college with well coordinated scheduling and such (e.g. calculus in a +1 situation, calculus and post-calculus math in a +2 situation).
When I went to high school, where the sequences were as described in reply #1, the two sequences listed were the “standard” ones (there was also a lower level -1 sequence leading to algebra 2 in 12th grade). Occasionally, there would be a +2 student, but the arrangements were definitely not “standard” and involved ad hoc commuting arrangements between the middle and high schools, and to a local college if desired to take math in 12th grade after completing calculus BC in 11th grade.