Spreadsheets also have financial functions built in. Here is how to compute the answer to example 3 using Excel:
First, enter to data in cells A1 through A6: -1800, 500, 500, 500, 500, 500
(1) Click on the cell where you want the answer displayed.
(2) In the "Insert" menu, choose "Function." (or click the function icon in your toolbar, [fx])
(3) Choose the "financial" function category, and choose "IRR" and a box pops up.
(4) Now fill in the array a1:a6 in the value box and ignore the guess box. Press enter
(5) The formula result displays in the cell you choose: 12.05%