Mathematics

Mathematics was the study of numbers.

Romulus and Remus Sylvest were mathematical geniuses. (TV: The Twin Dilemma) Peter Hutchings was a professor of mathematics at the University of Cambridge. (PROSE: Timewyrm: Revelation)

Some of the companions of the Doctor studied or taught mathematics. Jackson Lake was a mathematics teacher. (TV: The Next Doctor) Alistair Gordon Lethbridge-Stewart taught mathematics at Brendon Public School. (TV: Mawdryn Undead) Adric was awarded a gold star badge for mathematical excellence. (TV: Full Circle)

Block transfer computation
An application of mathematics known as Block Transfer Computation could be used to create objects and alter spacetime. (TV: Logopolis)

Recreational mathematics
The Tenth Doctor mentioned Recreational Mathematics, which involved the study of happy prime numbers. He seemed surprised it wasn't a regularly studied course. (TV: 42)