Calc has a wizard called the Function AutoPilot that helps you build formulas. To use the Function AutoPilot:
Click the cell that you want to contain the function.
Click the Function AutoPilot icon on the function bar.
In the Function AutoPilot window (Figure 20-5), select a function. Click Next.
In the second Function AutoPilot window, build the formula; see Figure 20-6.
When you're finished building the formula, click OK.