Control buttons appear at the top of the AddUp 2 window. Three buttons
to the left provide menu access. The leftmost button opens the main menu
which contains all options; pressing the *Alt* key does the same
thing. The second button marked with a *B* is a clickable shortcut
to the *Buttons* submenu. The third button marked with a
*?* is a similar shortcut to the *Help* sub-menu. Three
buttons to the right perform the usual Windows *minimize,
restore/maximize* and *close* operations.

The *Buttons* submenu controls various panels shown along the
left side of the window. Each panel contains a set of related calculator
buttons. Specific panels are selected by navigating the menu and checking
or unchecking them. All panels are either hidden or shown by checking or
unchecking the *Hide Buttons* menu option.

Open the *Buttons* menu, navigate to the *Functions*
submenu, on to the *General Mathematics* submenu and its
*Exponentials* submenu, then click on *Show the
"Exponentials" button panel*. A panel containing exponent,
power, logarithm and other related buttons will be shown on the left side
of the window. Now double-click the *Buttons* control button to
see how to quickly show or hide all calculator buttons.

Place the caret on an empty line in the work area. Click the
*exp* button of the *Exponential functions* panel. The
function is entered at the current caret position in the work area and
the caret moves inside the parentheses.

exp()

You can now enter a value for this function, say 1, and press
*Enter*.

exp(1) `= 2.71828`

This is the simplest mode of operation: the function name is inserted, then you provide the argument value. Now use the arrow keys or the mouse to return to the expression and highlight argument 1 like this:

exp(`1`) `= 2.71828`

With this selection in place, click the *ln* button of the same
panel to observe another mode of operation: the highlighted text
(whatever is selected) becomes the argument value of the new function
which gets inserted. Press *Enter* to see the result.

exp( ln(1) ) `= 1`

The exponent of the natural logarithm of 1 is indeed 1.

A third mode of operation selects an entire expression as function
argument. Place the caret anywhere on the line that contains the
expression you want to use. Hold down the *Ctrl* key as you click
the *fact* button:

fact(exp( ln(1) ))

The entire current expression is used as argument for the factorial
function. Press *Enter* to see that the factorial of 1 is also
1.