Class Libraries & REST APIs for the developers To manipulate & process Files from Word, Excel, PowerPoint, Visio, PDF, CAD & several other categories in Web, DeskTop or Mobile apps. Develop & deploy on Windows, Linux, MacOS & Android platforms....xls, is used. The spreadsheet has...you can see above, in Book1.xls, cell B7 contains a formula “=SUM(A1:A3)”...