Excel is organized to allow calculations laid out in tabular form -- much as we would lay out the same calculations if we were doing them with paper and pencil. The "paper" is called a worksheet in Excel, and it is divided into a rectangular grid by labeled rows and columns. The intersection of a row and column is referred to as a worksheet cell, and these cells contain all the data, text, and formulas that comprise a calculation and its associated documentation.Rows are labeled by numbers (1, 2, 3, ...) and columns are labeled with letters (A, B, C, ..., AA, AB, AC, ...). Cells are then labeled with both the column letter(s)and row number in that order. For example, the highlighted cell in the figure below is cell B2. A cell is selected (highlighted) by clicking the cursor over it. Only one cell can be selected at a given time and this cell is referred to as the active cell.
Notice also in the figure below the tool bars at the top of the worksheet. Many of these will be familiar to you from your work with word processors, and they serve very similar functions within the spreadsheet. Any text (used for documenting our calculations) entered in a spreadsheet can be formatted in a number of ways, including changing its font style, font size, making it bold, italics, and so on. Numerical data can also be formatted in a variety of ways as can be gathered from the tools ($, %, etc.) on the right side of the third tool bar.
The area just above the row of column labels contains a field giving the currently active cell (B2 in the figure) and an area where text, data, and formulas are shown as they are typed in, and where they can be later edited. This area is referred to as the formula bar.
Note: all screen shots in this tutorial are taken from Office97. The instructions have been updated for Excel 2000. The differences in the screen shots afor the two versions re minor and should pose no diffiuclties. These will be updated later.
Recall that a worksheet cell is made the active cell by clicking over it. Once this is done the cell is ready to accept data. In the figure below, we have selected cell B2 as the active cell and then typed in the word "Sales." As you can see the word appears both in the cell itself and in the formula bar. If we want to edit (or erase and replace) this word later, we simply click over the cell, then move the cursor to the formula bar where it becomes the standard text editing I-beam pointer. Editing takes place in the formula bar and is reflected in the cell when we click the Check box to the left of the formula bar (this will appear once we click to activate the formula bar in edit mode) or press the Enter key.
The following figure shows more text and numerical data entered into our example worksheet. The document has been saved and named Example1 in the figure.When entering data in multiple cells, we usually employ a quicker method than selecting every new cell individually. The Enter key completes entry in a cell and moves the active cell to the cell immediately below the current cell. The Tab key has a similar effect but moves the new active cell to the cell to the immediate right.
Notice in the figure below that we are about to format the numerical data that has been entered to of type currency. You'll see the effect of this in the next figure. The spreadsheet will automatically keep track of whether the data we have entered is textual or numerical (it will assume text except when the first character is a digit, a decimal point, or one of the algebraic signs + or -). Formulas are a third category and these always begin with an equals (=) sign. The formatting and other operations available will then be appropriate to the type of the data entered.
The following figure illustrates the process of entering a formula to compute the total sales for all six months shown. To enter a formula, we begin with the = symbol. Then we enter an algebraic formula, using the cell names (B3, B4, etc. in our example) instead of the actual data entered in those cells. The effect, of course, is the same. The worksheet will substitute the values entered in those cells when it does the arithmetic.The advantage of this scheme is that whenever we change the numerical data in any of these cells, the formula is still valid. The worksheet will simply pick up the new values when it makes it substitutions for the cell names in the calculation. This simple scheme of symbolically representing data in our formulas rather than entering the actual data is a major benefit of using a spreadsheet. This is because we can repeat and/or correct calculations at will -- without retyping the formula that captures the basic computation.
The following figure illustrates the results of entering the above formula into cell B10. Notice that once we enter the formula, the result of the application of the formula appears in the cell and the formula itself appears in the formula bar. Once we check the results of the calculation in the cell itself, the formula can thus be easily edited in the formula bar if necessary.
The following figure illustrates the results of entering new data into cell B4. Notice that the result of the application of the formula is automatically updated in cell B10 when this occurs. Alter some additional data and observe the results.
Now that you've practiced with your first spreadsheet calculation, you're ready to move on to the next lesson, where we'll explore the use of worksheet formulas in greater detail.
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