A statement indicating an assignment to a string or numeric variable (or an array element or structure member). LET can normally be omitted, and must be omitted in the case of assignment to the pseudo-variables LOMEM, HIMEM, PAGE, PTR# and TIME.
LET was mandatory in early versions of BASIC. Its use emphasised that when we write
X=X+4
we don't mean to state that X equals X+4 - it can't be, but rather 'let X become equal to what it was plus 4':
LET X=X+4
Most modern versions of BASIC allow you to drop the LET statement. However, if you are writing a program for a novice, the use of LET makes it more understandable.
Syntax
[LET] <var>=<exp>