Quick Tips for Using Formulas in Excel 2013
If you need your Excel 2013 spreadsheets to include mathematical calculations, you can use any number of Excel formulas. Excel formulas can do everything that a basic calculator can do, so check out these tips to find out how to quickly choose the formula you need:

A formula is a math calculation. Every formula begins with an equal sign.

The order of precedence determines the order in which math is processed in a formula: first parentheses, then exponentiation, then multiplication and division, and finally addition and subtraction.

Formulas can contain cell references that substitute the cell’s value for the reference when the formula is calculated.

When you copy a formula, by default, the cell references in it are relative, so they change based on the new position.

Placing dollar signs in a cell reference, such as $A$1, makes it an absolute reference so it doesn’t change when the formula is copied.

A function is a word or string of letters that refers to a certain math calculation. A function starts with an equal sign, followed by the function name and a set of parentheses. Arguments for the function go in the parentheses.

In functions, you can refer to ranges of cells, such as =SUM(A1:A4).

If you don’t know which function you want, choose Formulas→Insert Function.

The NOW function shows the current date and time; the TODAY function shows the current date.

SUM sums a range of cells. AVERAGE averages a range of cells.

MIN shows the smallest number in a range, and MAX shows the largest number in a range.

COUNT counts the number of cells in a range that contains numeric values. Two related functions are COUNTA, which counts the number of nonempty cells, and COUNTBLANK, which counts the number of empty cells.

Naming a range enables you to refer to it by a friendly name. Use the commands in the Defined Names group on the Formulas tab.

Quick Analysis provides quick access to common tools for analyzing data, including formatting, charting, adding totals, creating tables, and adding sparklines.