Household Calculator is a general purpose ergonomic calculator which combines use simplicity and calculation power. Household Calculator handles main arithmetic operations with two operands, addition, subtraction, multiplication, division, and complex formulas with unlimited number of operations and operands. For example, you can type in Edit Window such formula ((12.55+10.05+8.45+17.35)/30)*0.7-(13.45+15.76+2.05)*0.33 . Ergonomic design allows easily navigate through controls and enter data using both mouse and keyboard. The Household Calculator has three windows or boxes: Edit Window, Result Window, and History Window. In the Edit Window you enter formulas using buttons and keyboard. When you use a keyboard , you can use all standard rules of text editing. The most convenient is use of numerical pad on the right of standard keyboard. Buttons also provides full functionality of Household Calculator. If you mistake in typing formula, like square root of a negative number, you just get a message in the Result Window that the formula is unclear. The Household Calculator tries to handle all possible ambiguities, following the standard mathematical rules. For example, formula 3/-4 - 5*2 will be treated as 3/(-4) - (5*2) . If you want to be completely sure in the result, use parentheses. A result number in the Result Window can be copied into Edit Window by clicking Result button. Sometimes it is useful during calculations. For example factorial button is absent, but you can easily calculate 10! by typing formula 1*2*3*4*5*6*7*8*9*10 or by series 2*3, =, Result, *4, =, Result, *5, =, Result, *6, =, Result, *7, =, Result, *8, =, Result, *9, =, Result, *10, =, imitating "old style calculators". Calculation History Window has unlimited length. Use a scroll bar to navigate the window with log history. You can save the calculation history into text file or print it. Before this you can change size and style of the font in History Window.