Combining the operations of two or more functions, such as ROUND and SUM, in a single formula within Excel is often referred to as a nesting function. Nesting is accomplished by having one function act as an argument for the second function. Follow along, as we discuss how to properly nest functions and combine operations in Microsoft Excel.

### General Rules For Combining Functions in Excel

When evaluating nested functions, Excel always executes the deepest or innermost function first and then works its way outward. Depending on the order of the two functions when combined, the following applies:

- Rows or columns of data can be summed and then rounded to a set number of decimal places all within a single worksheet cell, row six above.
- Values can first be rounded and then summed, row seven above.
- Values can first be rounded and then summed, all in a single cell using a SUM/ROUND nested array formula, row eight above.

Since Excel 2007, the number of levels of functions that can be nested inside each other is 64. Prior to this version, only seven levels of nesting were permitted.

### Example: Combining ROUND and SUM Functions

Although it is possible to enter the complete formula manually, many people find it easier to use a function's dialog box to enter the formula and arguments.

=ROUND(SUM(A2:A4),2)

The dialog box simplifies entering the function's arguments one at a time without having to worry about the function's syntax — such as the parenthesis surrounding the arguments and the commas that act as separators between the arguments.

Even though the SUM function has its own dialog box, it cannot be used when the function is nested inside another function. Excel doesn't allow a second dialog box to be opened when entering a formula. Follow the steps below, combined with the image above for an example.

- Click on cell
**B6**to make it the active cell. - Click on the
**Formulas**tab of the ribbon. - Click on
**Math & Trig** - Click on
**ROUND**in the list to open the ROUND function dialog box. - Click on the
**Number**line in the dialog box. - Type
**SUM (A2 : A4)**to enter the SUM function as the**Number**argument of the ROUND function. - Click on the
**Num_digits**line in the dialog box. - Type a
**2**in the Num_digis line in order to round the answer to the SUM function to 2 decimal places. - Click
**OK**to complete the formula and return to the worksheet. - The answer 764.87 should appear in cell
**B6**since we have rounded off the sum of the data in cells**D1**to**D3**(764.8653) to 2 decimal places. - Clicking on cell C3 will display the nested function in the formula bar above the worksheet.

=ROUND(SUM(A2:A4),2)

### Using an Excel Array / CSE Formula

An array formula, such as the one in cell **B8**, allows for multiple calculations to take place in a single worksheet cell. An array formula is readily recognized by the braces or curly brackets **{ } **that surround the formula.

These braces are not typed in, however, but are entered by pressing the **Shift **+** Ctrl **+** Enter*** *keys on the keyboard. Because of the keys used to create them, array formulas are sometimes referred to as CSE formulas.

Array formulas are normally entered without the aid of a function's dialog box. To enter the SUM/ROUND array formula in cell **B8**:

- Click on cell
**B8**to make it the active cell. - Type in the formula
.*=*ROUND(SUM(A2:A4),2) - Press
**Shift**+**Ctrl**keys on the keyboard. - Press and release the
**Enter**key on the keyboard. - The value 764.87 should appear in cell
**B8**. - Clicking on cell B8 will display the array formula

{=ROUND(SUM(A2:A4),2)}

### Using Excel's ROUNDUP and ROUNDDOWN Functions

Excel has two other rounding functions that are very similar to the ROUND function — ROUNDUP and ROUNDDOWN. These functions are used when you want values to be rounded in a specific direction, rather than relying on Excel's rounding rules.

Since the arguments for both of these functions are the same as those of the ROUND function, either can easily be substituted into the above-nested formula in row six.

The form of the ROUNDUP/SUM formula would be:

=ROUNDUP(SUM(A2:A4),2)

The form of the ROUNDDOWN/SUM formula would be:

=ROUNDDOWN(SUM(A2:A4),2)