Excel and Lotus 1-2-3

Hello,

What is the relation between Lotus 1-2-3 and Microsoft Excel?

Thanks

Lotus 123 was the predecessor to EXCEL.

Thank you and can you explain this picture?

When enter slash(/) in excel environment,shows all excel command.

What is the relation with / and lotus 1-2-3 ? 

From Microsoft documentation:-

Lotus Compatibility

Microsoft Office Excel menu key     Sets the key that you can use to access the commands on the Ribbon, which is a component of the Microsoft Office Fluent user interface.

Transition navigation keys     Activates an alternate set of keys for worksheet navigation, formula entry, label entry, and other actions.

Lotus Compatibility Settings for     Select the worksheet in this list box that is affected by the following options.

Transition formula evaluation     Opens and evaluates Lotus 1-2-3 files without losing or changing information. When this option is selected, Excel evaluates text strings as 0 (zero), Boolean expressions as 0 or 1, and database criteria according to the rules that are used in Lotus 1-2-3.

Transition formula entry     Converts formulas that are entered in Lotus 1-2-3 release 2.2 syntax to Excel syntax, and makes names that are defined in Excel behave like names that are defined in Lotus 1-2-3.