Panels from Fantastic Four #133 (April 1973), written by Roy Thomas and Gerry Conway, art by Ramona Fradon, Joe Sinnott, and Stan Goldberg, lettering by John Costanza
1900+75=1973. To Reed, at least. Well, it's a good thing that his job doesn't depend on being precise with numbers...I mean, it's not rocket science, is it?
(Flashback) panels from Fantastic Four #261 (December 1983), written and drawn by John Byrne, colors by Glynis Wein, lettering by Jim Novak
Oh. Well, that explains that.