In VB, syntax is case-insensitive except for strings, such as Dim and dim.

Dim is the keyword of variable declaration, that is, you can declare a variable with dim. As "as" explains, integer is integer, and single is single precision (accurate to the third or third place after the decimal point, I forgot. ), string is a string class. For example, "Ni Hao A" is a string enclosed in English double quotation marks.

So the whole sentence means dim ... like ... (declaration ... like ... variable). If A is declared as an integer variable, then A will be an integer.

Variables are equivalent to unknowns in algebra in junior and middle schools.