The Jaden Smith and Jackie Chan-starrer has earned $56 million in first three daysThe Will Smith family acting dynasty is officially open for business. The actors 11-year-old son,Jaden,kicked his way to the top of the North American box-office recently in a remake of The Karate Kid,one of two new films cashing in on 1980s nostalgia. Columbia Pictures The Karate Kid earned an estimated $56 million during its first three days,vanquishing 20th Century Foxs The A-Team,a distant No. 2 with $26 million. Both films had been expected to vie for the top spot,each in the $30 million range.Last weekends champion,Shrek Forever After,fell to No. 3 with $15.8 million. The top five was rounded out by a pair of comedies that debuted modestly last weekend: Get Him To The Greek ($10.1 million) and Killers ($8.2 million). The two new arrivals helped the sluggish summer box-office end a three-week year-on-year decline. The top 12 films grossed $146 million,up about 11 per cent from the year-ago period,according to tracking firm Hollywood.com Box-Office.The Karate Kid,a $40 million Kung-fu picture co-starring Jackie Chan as the mentor of Smiths troubled inner-city kid,played strongly across all demographics. Exit surveys indicated that 94 per cent of moviegoers rated it either excellent or very good, said distributor Columbia Pictures.Its got tremendous heart,humour and depth, said Rory Bruer,president of worldwide distribution at the Sony Corp unit. He said the films underdog plotline and exotic locale most of it was shot in China worked in its favour. Thumbs up from Justin BieberIt did not hurt to get some help from Canadian teen heartthrob Justin Bieber,who sings the theme song and has been recommending the film to his young female fans. On the other hand,Ralph Macchio,the star of the 1984 original,said on Twitter that his films legacy remains untouched.Jaden Smith previously co-starred with his father in 2006s The Pursuit Of Happyness and as Jennifer Connellys stepson in 2008s The Day The Earth Stood Still. The opening of his latest picture almost quadruples the $15 million debut of Will Smiths most recent picture,the 2008 drama Seven Pounds. Smith and wife Jada Pinkett Smith were among the producers of Karate Kid. The A-Team did not inspire as much enthusiasm. The $95 million action drama about a team of renegade soldiers of fortune took years to make and was trashed by critics. But 20th Century Fox said the film played well with moviegoers aged under 25,a demographic with no first-hand memory of its camp,small-screen progenitor.The film stars Liam Neeson,Bradley Cooper,Sharlto Copley,and Quinton Rampage Jackson in the role of Mr. T. Fox is a unit of News Corp. Elsewhere,the four-week total for the DreamWorks Animation SKG Inc-produced Shrek Forever After rose to $210.1 million. But thats far short of what 2007s Shrek The Third ($283 million) and 2004s Shrek 2 ($347 million) had made at the same time in their runs. Sex And The City 2 is also falling short of its predecessor. The romantic comedy sequel,from Time Warner ncs Warner Bros. Pictures,has earned $85 million after 18 days,boosted by a $5.5 million weekend at No. 8. The first film had earned $121 million at the same stage in 2008.After 10 days of release,Universals Russell Brand comedy Get Him To The Greek has earned $36.5 million and Lionsgates Katherine Heigl-Ashton Kutcher romp Killers $30.6 million. Universal is a unit of General Electric Co. Lionsgate is a unit of Lions Gate Entertainment Corp.