iWork '09: The Missing Manual

Making Mini-Spreadsheets with Formulas

You can use tables for lists of pretty much anything, but very often tables involve some kind of calculation. When your table lists items in an invoice, you have a total amount due. When tracking student grades for a class, you show the average grade for each student. A table of monthly sales figures by product might add up the total annual sales for each product, as well as the total monthly sales for all products. You get the idea.

You might have heard about this already, but it turns out that computers are good at math. No need to strain your brain adding columns or figuring averages—when you use tables to list your data, Pages can run the numbers for you. In iWork, tables are actually spreadsheets and vice versa—any calculations that you can do in a Numbers spreadsheet, you can also do in Pages tables. This means that your clever tables can update calculations on the fly as you add new data. You can even swap these mini-spreadsheets back and forth with Numbers.

When you add a calculated value to a cell, Pages doesn’t simply run the numbers once and forget about it. It gives the cell a formula, a mathematical expression that tells Pages to do its arithmetic using other cells in your table. If you change a value of any of those cells, Pages automatically updates the formula’s result. A formula, in other words, is a smart placeholder that’s constantly updating its value as you add new data—formulas keep your tallies up to date so that you don’t ...