=DATEDIF(Date1, Date2, Interval)

where Date1 and Date2 are the two dates and Interval defines how the date difference should be returned. Interval must be enclosed in quotes like this:

=DATEDIF(Date1, Date2, “d”)

These are the errors that DATEDIF may return if you get something wrong:

• #NUM error if Date1 is later than Date2
• #VALUE error if either Date1 or Date2 are invalid dates
• #NUM error if the Interval specified is not one of the allowed values

The Interval must be one of the following values:

DATEDIF Examples

Try and predict what the result of the following examples will be:

• the starting range to which the offset is to be applied – this can be one cell or a range
• the number of rows to offset the starting range by – this can be negative
• the number of columns to offset the starting range by – this can be negative
• the height of the new range in rows
• the width of the new range in columns

The syntax for the Excel offset function is as follows:

=Offset(range, rows, columns, height, width )

Let’s consider the following data in a worksheet:

Performing the offset

=Offset(B3, 2, 1, 1, 1 )

gives the contents of cell C5, i.e. 7.95.

Performing the offset

=Offset(D5, -3, -2, 2, 2 )

gives the contents of the cell range B2:D4

Let’s consider the following cells in a spreadsheet:

After typing =COUNT(A1:A6) and pressing Enter, Excel calculates the count to be 4.  There are 6 cells in the selected range, but one contains the word “dog” and one cell is blank. That means there are 4 cells that contain numeric values and so the count is 4.

Count Nonblank Cells

There is another count function that you can use in Excel: COUNTA. COUNTA returns a count of all the nonblank cells in a range.

Consider the following spreadsheet:

There are 6 cells in the range A1:A6. 2 are blank, 2 contain words and 2 contain numbers. This means that there are 4 nonblank cells (2 numbers and 2 words) so the COUNTA function returns 4.

For example, look at the following spreadsheet that contains data about sales by month for the year 2010.

When we type the title “Sales By Month For 2010″, we can see that it spills out into other cells. It would help if we could merge all the cells above the table headings for the title to occupy and also center the title. We can do that with just one button: the Merge and Center button.

Select cells A1 to D1 and then click Home > Alignment > Merge and Center. Cells are merged and title centered! Press Cctrl-b to bold the text and there we have a nice looking title.

Merge And Center Vertically

We can do a similar thing vertically for row headings. Suppose we move our table to the right by one cell to make room for a row title.

Now, we can type the text “Months of the year – 2010″ in row A14. The text needs to be in the bottom row because we’re going to rotate the text anticlockwise, as we’ll see.

Select cells A2 – A14 and then click the Merge and Center button. Those cells are merged, but we can’t see all the text. Now click the Orientation button, also in the Alignment group.

Select Rotate Up, and we should get the following:

Hold on, we selected Merge and Center, but the text isn’t centered. What’s wrong? Well, the text is centered – horizontally. It needs to be centered vertically, so we need to click the Middle Align button in the Alignment group.

This does the trick, so all that’s left to do is press ctrl-b to bold the text.

• First Name
• Last Name
• Age
• Salary

Each row in the table would hold the above details for a particular employee. But as Excel 2010 handles tabular data perfectly well by default, why would you want to put your data into a table? Well, tables allow Excel to respond more appropriately to your data if it is held in a a table. For example, if you create a chart based on the data in a table, the chart will expand as you add more rows to that table.

Creating Tables In Excel 2010

It’s quite easy to create a table in Excel 2010; you simply make a cell active that is in the range of cells you want to convert into a table and then click Insert > Tables > Table. If your data has headers, make sure to check the My table has headers box in the create table window, and then those headers will be used. The good thing is that you don’t need to select the entire range of cells: Excel can identify the limits of the data and also identify the headings. The following is an example of tabular data before we convert it into a table.

After we convert it to a table, it looks like this:

If you create a table this way, it is given default formatting that you can change using the Table Styles on the Design tab that appears when the table is selected. Alternatively, you can select a style when you create the table. To do this, activate any cell in the range you want to convert and click Home > Styles > Format as Table. Choose a style from the panel that opens and your table will be created with that style.

Properties Of Excel Tables

The main things to notice about tables are:

• When any cell in the table becomes active, the Table Tools contextual tab is displayed.
• Each column heading contains a drop down list that you can use to sort or filter the data in that column.
• If you scroll so far down the table that the column headings disappear, the letters that mark the column headings in the worksheet are replaced with the table’s column headings.
• The cells have background colours to enhance readability.
• Background colours are applied to the cells to help readability.

Deleting An Excel Table

If you later decide that you’d prefer your data in its original form (i.e. not in a table), you can convert it back to a range of cells. Click anywhere in the table and then on the Table Tools tab, click Design > Tools > Convert To Range. Once the data is converted back to a range, the table features are no longer available.

Note that the formatting that was applied to the table is still present.

If you want to delete the table and all its data, select the table and press the delete key.

Different Ways To Sum Data In Excel

Using The Status Bar

If you select a number of cells, Excel displays their total, amongst other things, in the status bar.

The status bar is positioned at the bottom of the window. The sum value displayed there updates immediately as you select more or fewer cells. Also displayed there are the average and cell count values. To select or deselect values for display on the status bar, right click the status bar and either check or uncheck the options presented.

Excel Autosum

The autosum function in Excel is so useful it appears on both the Home tab and the Formulas tab. If you have a column of numbers, you can make the cell below that column active and click Home > Editing > Autosum.

To confirm that Excel has the correct range of cells, press Enter or click the autosum button again. Excel then displays the value of the sum.

Similarly, if you have a row of numbers, you can use the autosum function to sum them. In this case, make the cell active that is positioned to the right of the row and click the autosum button.

The Sum Function

Excel also has the SUM function that we can use. To enter a simple sum formula, type =SUM in a cell, followed by an opening parenthesis. Next, type one or more numbers, cell references, or cell ranges, separated by commas. Then, type a closing parenthesis and press ENTER to display the result. You can also use your mouse to select cells that contain data that you want to sum.

For example, look at the image above used to illustrate autosum. The cell that holds the sum has the formula =SUM(A1:A6).

Sparklines were developed by Edward Tufte to give a simple, condensed way to present trends and variation, associated with a measurement such as average temperature or stock market activity.

Let’s get stuck in and create some sparklines in Excel now. You can use the simple example here.

Open up the worksheet and then click in cell G3 to make it active. We’re going to insert a sparkline in this cell that represents the monthly fuel bills to its left. It helps to position a sparkline near its data for greatest impact. With G3 active, click Insert >Sparklines > Line.

Excel has already identified cell G3 as the Location Range because that was the active cell. We now need to tell Excel what data to use for the sparkline, and we can do that by selecting cells A3 to F3. When these cells are selected, Excel puts A3:F3 into the Data Range box. Click OK and a line sparkline  is created.

Whereas charts in Excel are objects, sparklines are actually placed in a cell’s background. This means that you can enter text in a cell and use the sparkline as its background. For example, we could type some text into cell G3 and the sparkline would act as its background. Some people may not like the way that text inserted in this way obscures the tiny sparkline.

There aren’t many formatting changes we can make to this sparkline, but let’s make some that may prove useful. Let’s add some markers. With cell G3 active, you should see the Sparkline Tools tab in the ribbon. Click Design > Style > Marker Colour > High Point, and select a colour that contrasts with the line colour. Do the same for the Low Point too.

To delete a sparkline from a cell, pressing the delete key will do you no good! This is because the sparkline is in the cell’s background. Instead, you need to click the Clear button on the Design tab.

Let’s leave the line sparkline where it is and create a column sparkline below it so that we can compare them. Make cell G4 active and click  Insert >Sparklines >Column. Select the data cells again and click OK. Now, we have the following sparklines:

If you decide to change the sparkline’s type, you can simply click on the one you want in the Type group on the Design tab. The sparkline will immediately change to that type.

and you copy the formula to cell C2, you will get =A2+B2. This is because the cell references are relative. The contents of cell C1 are calculated to be the sum of the the cell that is 2 cells to the left and the cell that is 1 cell to the left. This easily transposes to cell C2.

To demonstrate, I copied cell C1 to cell C2 and got this:

You can see in the formula bar that the original formula of =A1+B2 has been transformed to =A2+B2 when copied to cell C2.

But what if we want to always use A1+B1 in all cells we copy that formula to? This is where absolute cell references come in.

How To Construct An Absolute Cell Reference

In Excel, we create an absolute cell reference by using a “$” before each letter and number. The formula for C1 then becomes

=$A$1+$B$2

Copying that formula to C2 retains those absolute references and we find the that C2 also uses =$A$1+$B$2.

You can also mix ansolute with relative references like this: A$1. Here the row is fixed at one, but the column remains relative.

You can easily tell what the cell reference is by looking at the cross section of the row and column for that cell. For example, the cell below occurs at the cross section of column C and Row 3.

The cell reference is therefore C3 and we can use C3 to refer to the data in that cell.

We can use cell references to refer to:

• Data from one cell in your worksheet.
• Data that is contained in different areas of your worksheet.
• Data in cells on other worksheets in the same workbook

Cell References For A Range Of Cells

C3 refers to the contents of just one cell. What if we want to refer to a range of cells?

Consider the following range of cells.

The range goes from cell D2 to D4 so the range is denoted by D2:D4.

So far we have looked at cell references on the sme worksheet. Let’s now look at references to cells on different worksheets.

Cell References On Other Worksheets

Suppose that we are using two worksheets in the same workbook: Sheet1 and Sheet2. We are creating a formula in Sheet1 that uses data in cell E12 on Sheet2. The reference to this cell is simply Sheet2!E12. Don’t forget the exclamation mark after the worksheet name.

For example, let’s suppose that we are working on Sheet1 and we want to sum the values of cells A1 to A10 on Sheet2. The formula would be

=SUM(Sheet2!A1:A10)

Dont worry too much about how to create formulas, the important part is the Sheet2!A1:A10. Note that the Sheet! bit tells Excel that the cells are on Sheet2 and the A1:A10 bit tells Excel that it’s dealing with the range of cells A1 to A10.

By default, cell references in Excel are relative, however, we can use absolute references in Excel too.