His son, Chris, says the 94-year-old Dorough died of natural causes Monday at his home in Mount Bethel, Pennsylvania. He released his first album, "Devil May Care", in 1956, and the title track would go on to be covered by Miles Davis, among others.
His granddaughter Corin Wolf didn't disclose his exact cause of death but told CNN that Dorough was diagnosed with cancer past year.
Born on December 12, 1923, in Cherry Hill, AR, Dorough was a jazz musician in the early 1970s when a NY ad man complained that his young sons couldn't do multiplication and wanted to have the times tables set to music because the kids could recite every rock lyric of the era.
Dorough was born in Arkansas and raised in Texas.More news: Shire considers Takeda's revised £46bn takeover offer
More news: Video shows Minnesota fugitive grandmother's arrest in Texas
More news: NFL Draft Rumors 2018: Bills Unlikely To Trade To No. 2
Dorough ended up writing "Three's a Magic Number".
"I got the idea that three is a magic number", Dorough told NPR in 2013.
Dorough wrote and/or performed many of them, not including "I'm Just a Bill", which famously was spoofed on Saturday Night Live in 2014.
The song spawned the album Multiplication Rock and the concept was later sold to ABC executive Michael Eisner, ultimately becoming the first iteration of Schoolhouse Rock!. Expanding to cover grammar - Dorough's least-favorite subject to pen music on - American politics and history and science, the initial series ran for 12 years and was revived in the "90s".
Dorough, a jazz pianist and vocalist, wrote his first "Schoolhouse Rock" tune after a NY advertising executive approached him in 1971.