Omnicalc provides a custom menu for your 83+, much like the CUSTOM menu on a TI-86. You can store frequently used functions from the Catalog in the CUSTOM menu for quick access. To access the custom menu, press VARS twice. To paste a function from the custom menu, scroll to it and press enter, or press the numeric key that corresponds with its entry.
Your custom menu will be empty at first. To put a function in a slot in the custom menu, go to the catalog by pressing 2nd+Catalog. Scroll to the function you want to insert and press On and the number of the slot to fill. For example, to put abs( in slot 4 you would scroll to abs( and press On+4. To remove a function from the custom menu, first press VARS twice to access the menu. Scroll to the item and press Del.
Omnicalc modifies the existing log() function on the calculator to provide support for arbitrary log bases. log() with a single argument, such as log(20), will take the log base 10 of 20. However, there is also a format log(number,base). This function only works with real numbers. For example:
When you press CLEAR at the homescreen, typically it erases the entire line. With Omnicalc, a 89-style CLEAR functionality is enabled, depending on the cursor location. If the cursor is at the end of the current entry in the homescreen, pressing CLEAR will erase the entire line. However, if the cursor is located inside the entry, pressing CLEAR will erase only tokens to the right of the cursor. Pressing CLEAR immediately again will clear the entire line.