Add "at" before the page

Error²Federal courts, Illinois courts21st and 22nd editions

“Id.” alone repeats the previous citation's own page. Pointing to a different page or footnote in that same case is introduced by “at”, as in “Id. at 8”.¹

1. 1B10.2 Short Form Citation. Tables: R. 10.9(a)(i) Generally.
2. 2An error: the rule in note 1 allows one form, and this is not it.