LOS ANGELES — “X-Men: First Class” had a solid No. 1 opening with a $56 million weekend, according to studio estimates Sunday.

But the 20th Century Fox prequel chronicling the formative years of the comic-book mutants found smaller audiences than the franchise’s first four big-screen adventures, which featured older versions of the X-Men.

The original “X-Men” opened 11 years ago with $54.5 million, but that would amount to about $80 million today adjusting for ticket-price inflation.

Fox distribution executive Chris Aronson said the studio achieved its goal of opening the prequel at about the same revenue numbers as the original “X-Men.”

“This is just an excellent start in launching a brand new chapter of the ‘X-Men’ franchise,” said Aronson.

The previous weekend’s top movie, Warner Bros.’ “The Hangover Part II,” fell to second-place with $32.4 million.

DreamWorks Animation and Paramount’s sequel “Kung Fu Panda 2” slipped from second- to third-place in its second weekend with $24.3 million.

Estimated ticket sales for Friday through Sunday at U.S. and Canadian theaters, according to Hollywood.com, are:

1. “X-Men: First Class,” $56 million

2. “The Hangover Part II,” $32.4 million

3. “Kung Fu Panda 2,” $24.3 million

4. “Pirates of the Caribbean: On Stranger Tides,” $18 million

5. “Bridesmaids,” $12.1 million

6. “Thor,” $4.2 million

7. “Fast Five,” $3.2 million.

8. “Midnight in Paris,” $2.9 million

9. “Jumping the Broom,” $865,000

10. “Something Borrowed,” $835,000.