Spacey plays a maths professor in 21 who leads his students astray
Las Vegas gambling drama 21, which stars Kevin Spacey, has led the UK and Ireland box office for a second week.
The film, based on the true story of a group of US students who employ card-counting techniques to cheat a casino, took £1m in its second week.
Fool's Gold was second. Kate Hudson and Matthew McConaughey star in the treasure-hunting adventure comedy.
In Bruges, a black comedy about two hitmen starring Colin Farrell and Ralph Fiennes, climbed from 17 to three.
UK AND IRELAND BOX OFFICE
1. 21 (£1,010,758)
2. Fool's Gold (£975,498)
3. In Bruges (£638,654)
4. Street Kings (£619,647)
5. Son of Rambow (£583,251)
Source: Screen International
George Clooney's American football drama Leatherheads, which co-stars Renee Zellweger, fell the furthest down the chart, from number six to number 12, with takings of £177,141.
Another new entry, Keanu Reeves action thriller Street Kings, was fourth.
It stars Reeves as Tom Ludlow, a troubled Los Angeles policeman who has to deal with both the death of his wife and being implicated in the execution of a fellow officer.
Schoolboy drama Son of Rambow dropped from two to number five, while romantic comedy 27 Dresses, fell from number three to number eight.
Also dropping down the chart were Fantasy film The Spiderwick Chronicles, from four to six, and urban dance movie Step Up 2 the Streets, which went from five to seven.
The last new entry in the top 10 was Happy-Go-Lucky, a quirky comedy about an upbeat primary school teacher and her relationship with a dour driving instructor, directed by acclaimed British director Mike Leigh.
And down three places at 10 was Dr Seuss adaptation Horton Hears a Who, the animated tale of an elephant trying to save a microscopic world on a speck of dust.