Changing the Background Color of Cells and RangesYou can add even more pizzazz to your spreadsheets by changing the background color of individual cells or ranges of cells. This sort of shading is useful when you want to highlight information in a spreadsheet, as shown in Figure 30. Figure 30. A spreadsheet with cells shaded different colors.
To change the background color of a cell or range of cells, follow these steps:
Figure 31. Choosing a cell background color.
Tip When you change the background color for a cell, be sure the text color is a good contrast to the background color. You don't want green text on a green background, for example; strive for a readable contrast in colors. 
Section 11. Entering and Editing FormulasAfter you've entered data into your spreadsheet, you need to work with those numbers to create other numbers. You do this as you would in the real world, by using common formulas to calculate your data by addition, subtraction, multiplication, and division. You can also used advanced formulas preprogrammed into Google Spreadsheets; these advanced formulas are called functions and are explained in the next section. If you're an Excel user, you're used to using formulas. If you're new to spreadsheets, it helps to know that a formula is a mathematical expression that defines the relationship between two or more values. In Google Spreadsheets, formulas are used to calculate values for specific cells and can use common mathematical operatorsas well as references to other cells in the spreadsheet. 
Understanding FormulasFormulas are used to calculate the values of data entered into other cells in your spreadsheet. A formula can consist of numbers, mathematical operators, and the contents of other cells (referred to by the cell reference). Note The cell reference is simply the location of a particular cell. Each cell is referenced by the intersection of a column and row; thus, the topleft cell is called A1 (for column A, row 1). The cell reference for the current cell is always listed in the Reference area of the workspace. You construct a formula from the following elements:
The best way to get used to formulas is to look at a few. That said, Table 8 shows a few representative formulas:
Note that Google Spreadsheets formulas can contain common algebraic expressions and follow common algebraic conventions and logic. Table 9 lists the accepted operators for Google Spreadsheets formulas.
