As a result, nesting functions allows for multiple calculations to take place in a single cell - something that is not normally allowed in Excel.
In Excel 2003 you can have 7 levels of nested functions, while in Excel 2007 and 2010 you are allowed to nest up to 64 functions.
The Order for Solving Nested Functions in Excel
When evaluating nested functions, Excel executes the deepest, or innermost function, first and then work its way outward.
Nested Functions Example
= ROUND(SUM (D1 : D3), 2)
In the example, Excel would first find the sum of the values in cells D1 to D3 and then round that figure to two decimal places.
Related Tutorial: Nested ROUND and SUM Function Tutorial