Household Accounting Book offers you several useful supplementary functions in the "Tools" menu.

The calculator has implemented the basic mathematical operations such as subtraction, addition and percent-evaluation. You can use this tool for basic calculations. With the currency calculator you can convert values from one (stored) currency into another. To add or change a specific currency select "Preferences" in the applications menu and go to the tab "Currencies" (refer also to Input/Output). In addition, there is a basic shopping list that lets you keep track of the items you need.