From QB64.org wiki
The LET is a useless statement designed by cavemen when they started programming.
- [LET] variable = expression
- LET a = 12 is the same as a = 12, but wastes 4 extra bytes of program space.
- Teachers should be SHOT for even teaching about it! Move on!
Notes: LET is optional, it's the only keyword where the entire keyword is optional :-)