The Crackulator is designed to be used with the keyboard for extreme calculation efficiency. It's designed to be intuitive - just try it!
Normally, the cursor will be positioned in the last Input field you used. Type a number, and press Enter, and that number will be entered on the stack, and the cursor will be sent back to the last-used Input field. For min/max and nom entries, pressing Enter will take you to the next field before submitting to the stack.
Elemental calculations [+], [-], [*], and [/] can be performed on the items on top of the stack just by pressing the desired operation.
(There is one ambiguity to this; if you press [-] in a number-entry field, it doesn't know if you mean to put a '-' in the field, or to perform a subtraction on the stack. It will put the '-' in the numerical field, and you can use the mouse for a subtraction. As an alternative, you can press [Shift][-] to perform the subtraction.)
If you have already entered all the "Input" you need to enter, pressing any of the elemental calculation buttons will automatically send your number to the stack, and then perform the calculation. So to add 1 and 1, you can just press  [Enter]  [+].
There are also the following shortcuts: