(a) “Class” means a group of pupils scheduled to report regularly at a particular time to a particular teacher during the regular school day as defined by the school district governing board, excluding special day classes. Classes in the evening and summer schools are not classes for purposes of this section.

(b) Where the type of teaching in kindergarten and grades 1, 2, and 3 is other than in self-contained classes, the “class” is the basic homeroom where all of the following applies for a pupil:

(c) “Kindergarten” includes transitional kindergarten as defined by Education Code section 48000.

(d) “Active enrollment count” for purposes of subdivision (e) means the count of pupils enrolled in the class on the first day of the school year on which the class was in session, plus all later enrollees, minus all withdrawals since that first day. A pupil who is enrolled in independent study pursuant to Article 5.5 of Chapter 5 of Part 28 of the Education Code for the full regular school day shall not be included. An active enrollment count shall be made on the last teaching day of each school month that ends prior to April 15 of the school year.

(e) The “average number of pupils enrolled per class” for kindergarten and grades 1, 2, and 3 is the number obtained by dividing the sum of the active enrollment counts made under subdivision (d) for each of the classes in those grades, by the total number of those active enrollment counts.

(f) “Average class enrollment” means the sum of the average number of pupils enrolled per class determined pursuant to subdivision (e) for all kindergarten and grades 1, 2, and 3 classes at a school site, divided by the number of classes, then rounded to the nearest half or whole integer.

(g) “Maximum average class enrollment” for purposes of section 15498.3 means the amount determined by subtracting the current year average class enrollment adjustment pursuant to Education Code section 42238.02(d)(3)(B)(v) from the prior year average class enrollment pursuant to Education Code section 42238.02(d)(3)(B)(i), then rounded to the nearest half or whole integer. Commencing with the 2014-15 school year, the prior year average class enrollment for purposes of Education Code section 42238.02(d)(3)(B)(i) is the maximum average class enrollment in the prior year.