Notes about the NM file extension:
To open this file type, a required software must be installed. Without it you only see a Windows message "The following file cannot be opened
" (Windows 7) or "How do you want to open this file?
" (Windows 10) if you double-click the file. There click on "More apps"
and choose a suitable software to view such files on your PC or from email attachments.
The NM file type is primarily associated with 'RM Number Magic' by RM plc. RM Number Magic is a package covering information handling, modelling and monitoring, which helps primary schools to meet the curriculum requirements for ICT.
Detailed information for file extension NM:
File classification: Spreadsheet
To change file associations press Windows Key
and then Apps and Features
> Default apps
> Choose default apps by file type
Invalid file associations could be the result of underlying issues within your Windows PC.