The "less than or equal to" function in Microsoft Excel is denoted by the symbols "<=", with the lesser value on the left side of the equation. This function is known as a "comparison operator," and it can be used in a variety of equations, functions and tests in Microsoft Excel.

A common use of the "less than or equal to" function is a logical test for an "IF" statement in Microsoft Excel. The formula commonly looks like "=IF(A1<=B1, [True],[False])", where A1 and B1 are the two values in cells A1 and B1 that are being compared. In this example, the test would return a "True" response if the value in cell A1 is less than or equal to the value in cell B1 and a "False" response if it is greater.

The IF statement is broken into three parts, separated by commas, after the first parenthesis. The first part is called the logical test, where the "less than or equal to" test is contained. Other comparison operators also function in the IF statement, such as "less than" (<), "greater than" (>), "greater or equal to" (>=), "equal to" (=) or "not equal to" (<>). The next part is what the IF statement returns if the test is true, and the last part is what it returns if the test is false.

IF statements and comparison operators are great for analyzing large amounts of data and make a good conceptual starting point for understanding other functions in Microsoft Excel.