Excel VBA Pound and Colon Signs Meaning?

The colon (:) is a statement delimiter. It would be equivalent to a new line in VBA, or a semicolon in C (just to quote a random example). It allows you to write several instructions on a single line rather than going to a new line each time.

The pound (#) is a short-hand type specifier that forces your literals to be double, so basically 1# is almost equivalent to 1.0.

****Here is a Cheat Sheet for DataTypes ****

Variable End with:

$ : String
% : Integer (Int32)
& : Long (Int64)
! : Single
# : Double
@ : Decimal

Start with:

&H : Hex
&O : Octal

Visual Studio .Net added Literal Types (reference)

Value End with: (For more complete list, refer the the reference)

S : Short (Int16)
I : Integer (Int32)
L : Long (Int64)
F : Single
R : Double
D : Decimal