Related Information for Sum 41 Sum 41 is a Canadian punk rock band from Ajax, Ontario, Canada, active since 1996. The current members are Deryck Whibley (lead vocals, rhythm guitar), Jason McCaslin (bass guitar, backing vocals), and Tom Thacker (lead guitar, backing vocals, keyboard). They've released five studio albums.Sum 41 released their debut album, All Killer No Filler, in 2001 and achieved mainstream success through the album's first single, "Fat Lip", which reached number-one on the B.. read more