In Brief: 
This game develops the ability to quickly think forwards and backwards, something musicians must do constantly. Speed is like Slow except with 5 cards rather than 3 and without taking turns. It's wildly fun.
Quickly (and we mean quickly) think forwards and backwards in quick succession
Prerequisite Concepts: 
Secure knowledge of note and rest values, ideally gained by all previous Music Mind Games rhythm math games
Teacher's Role: 
Observe or play with students