Halloween Kills and Ends are the 12th & 13th Halloweens, 11th & 12th Michael Myers's, third Halloweens 3 and 4, and the last two films of the second trilogy, respectively. It's not that hard

Halloween (2018) is a direct sequel to Halloween (1978) (it ignores the brother-sister stuff from Halloween II), making it the 3rd "Halloween", the 11th Halloween movie, 10th Michael Myers movie, and the 3rd Halloween 2.

Rob Zombie Halloween is the 9th Halloween, eighth Michael Myers, the second "Halloween", and the 4th separate storyline. Zombie's Halloween II is number 10 in the series, the 9th Michael Myers, and the second Halloween II.

Halloween H20: 20 Years Later is the 7th Halloween, 6th Michael Myers, and a direct sequel to Halloween 2 since it ignores Laurie Strode's death from Halloween 4, making it the second Halloween 3. Halloween: Resurrection is the 8th Halloween movie, 7th Michael Myers one, and Halloween 4 number 2.

Halloween 4: The Return of Michael Myers is the 4th Halloween movie and the 3rd Michael Myers. Halloweens 5 & 6, The Revenge and Curse of Michael Myers, respectively are the fifth and 6th Halloween movies, 4th and fifth Michael Myers films, and the second and 3rd parts of the Thorn Trilogy.