- Inputting data
- Identifying cells
- Cell ranges
- Entering formulas
- Relative versus absolute cell references
- Formatting cells

Excel is a type of computer program called a spreadsheet. It is probably the most widely used program for the management and analysis of numeric data, and is heaviely used in the scientific as well as the business communities. The utility of Excel and other spreadsheet programs comes from its visual method of storing and management of data. Each unique bit of data is held in a

cell. Each cell has a unique location and can be referenced to format the display of the numeric data, create graphs, and perform mathematical operations on the data.

You can enter data by simply

clickingon one of the cells in the spreadsheet andtypingin your values. Normally you will start entering somewhere near the upper left corner of the spreadsheet. You can move to the next cell in a number of ways:

Clickingon the next cell you want to enter data intoReturnwill move to the next cell downTabwill move to the next cell to the rightArrowkeys will move in the direction of the arrowReferring to the figure above, the first row of data might be entered:

1 Tab 52 Tab 48 Tab 73.5The first column might be entered:

1 Return 3 Return 2 Return 5 Return 2Data in a cell can be deleted by

highlightinga cell and eithertypingin a new value or hittingDelete.

Each cell is located in a rectilinear grid of cells and is located by a column and row designation.

Columnsare designated byletterswhilerowsare designated bynumbers.In this piece of an Excel spreadsheet, the number

74is located in cellC3. Notice that the location designation of the highlighted cell is shown on the right of the first tool bar above the spreadsheet (called theformula bar). Similarly, the value of the cell is also shown in the formula bar. Every other number in this spreadsheet can be located with a unique letter-number designation.

Groups of cells can also be specified by placing a colon between the upper left and lower right corners of the group of cells. For example:

This highlighted column of cells would be

B1:B5. Notice that the letter designation is the same for a single column of cells. Another selection might be:Here, multiple rows and columns are selected and would be designated as

A2:C4.

The power of spreadsheets is not just in being able to hold numbers, but also manipulating them with mathematical

formulas. A cell is designated as having a formula in it by typing anequal(=)signas the first character. Next comes a combination of cell designations and/or standard mathematical operators (+,-,*,/) and/or special predefined functions. For example:A formula is entered in cell

B6, starting with theequalsignfollowed by the special functionSUM(). The cells to be summed are specified inside the parentheses. In this case cellsB1toB5are summed. The entry ofB1:B5into the function could have been done bytypingthe letters or byclicking and draggingon the range of cells of interest. Note that the formula is also shown up in the formula bar. You can accept the formula either by typingreturnor by clicking on thegreen checkmarkto the left of the formula. Cell B6 now shows the result of the formula calculation:A complete list of functions can be found by clicking on a cell and choosing

Insert>Function...in Excel-2003 (and inThe Formulassection in Excel-2007).

Most formulas are applied numerous times to different groups of cells, referring to a different range of cells each time it is used in a different cell location. Because of this, Excel provides a behavior to speed the updating of cell references. Supposed you had your SUM formula entered in B6 and you wanted to use it to sum the values in column C. You might select

B6, chooseEdit>Copy, selectC7, and chooseEdit>Paste. (In Excel-2007, chooseHome>Copy, andHome>Paste).Notice up in the formula bar that the SUM function now operates on

C1:C5. When the formula was copied over one column (B6toC6), the range of cells referred to in the function also shifted one column (B1:B5toC1:C5). This is because the cell references in the function wererelative references.If you do not want the cell(s) that a formula refers to shift relative to where the formula is copied, you must use

absolute references. You can do so by putting adollar ($) signbefore the letter and/or number in the cell designation. For example, say your formula refers to a constant located in cellE7:If you had simply entered the cell reference as

E7, when the formula inB7was copied toC7, the reference toE7would have shifted toF7. This would be undesirable. Instead the constant is referenced with$E$7. Now when it is copied:The formula in C7 still refers to cell E7.

Placing a single dollar sign in front of the Column letter (e.g., $E7) or Row number (e.g., E$7) will then fix the column or row to an absolute reference but allow the other parameter to be a relative reference.

Often when data are inputted into cells, the numeric values are not formatted the way you would like them to appear in the spreadsheet or in graphs you will later create. The number of decimal places, along with many other formatting options can be set by selecting the cell or cells you would like to format and choosing

Format>Cells...(In Excel-2007, chooseHome>Numberlink at lower right).When you first click on the

Numbertab, your cells will be listed in the Category General. This is the default data category for a new spreadsheet. To control the decimal places, you will need to change theCategorytoNumber. Nowtypeorclickthearrowsto set the appropriate number ofDecimal places. A preview of what your formatted cell(s) will look like is shown in theSamplebox. You can also control howNegative numbersappear. For scientific applications, you usually leave it at the default seen here.Though in this example, the number of decimal places has been changed to two places, the underlying value stored in the spreadsheet has not been rounded:

Note for the highlighted cell, the full five decimal places still show up in the formula bar.

The number of decimal places can also be controlled with the tool bar icons: