One of the most popular office tools are certainly spreadsheet calculators.
Lotus 1-2-3 was certainly one of the most popular programs. Some versions of 1-2-3 are apparently available as abandonware, maybe I will some of those later.
There were, however, alternatives programs to Lotus 1-2-3. One of the shareware options was As-Easy-As.
The owner of As-Easy-As, TRIUS Inc., decided to release the DOS version of their spreadsheet by providing the necessary codes.
Here is a link to TRIUS Inc's very own forum post on their forum page, providing downloads for the program and the user manual, as well as license codes for the DOS version of As-Easy-As and the respective documentation for free!
Please note that the codes for the program and the manual are different.