“Schoolhouse Rock” was actually filled with jazzbos. One of them just died: Blossom Dearie, the voice of “Figure Eight,” “Unpack Your Adjectives” and “Mother Necessity.” She has a great version of Antonio Carlos Jobim's “Wave” that is worth seeking. RIP

Bob Dorough, another well-known jazz player who worked with Dearie frequently, composed and sang a lot of the songs, including “Three Is A Magic Number.” He was one of the few people to sing on a Miles Davis record.

The other major female voice was not a jazz singer: Lynn Ahren, who was then a secretary at the advertising firm that produced these shorts for ABC. She wrote and sang “Interplanet Janet” – then went on to become a major Broadway composer, doing “Ragtime,” “My Favorite Year” and “Seussical.”