# Summary

An expression is anything in your code that the evaluator needs to work out.

Numbers like 0, 10, and -11 are called constants, because they never change.

When the CPU’s evaluator computes a number, you have a numeric expression.

There are several numeric data types. Integers and longs are whole numbers. Singles can have fractional parts.

Use operators and function in expressions, to do calculations. Some operators have a higher priority than others.

Try to put text into a numeric variable, and Bad Things happen. You can use input validation to check data, before you put it into a numeric variable.

A string can have letters (ABC… abc…), digits (0123456789), and special characters. “Pintrest” is a string constant. The simplest string constant is “”, the empty string.

The concatenation operator, &, sticks strings together.

There are many string functions. They change case, strip spaces, find one string inside another, return parts of a string, etc.

Logical expressions are either true or false. They are mainly used in If statements. Comparison operators like <= and <> compare two numeric or string values, and are either true or false. Not, And, andOr combine the results of logical expressions, like empCount >= 1 And empCount <= 6.

There are many ways to write the same If test. Use whatever is easiest for you to understand.