Currently Calc is missing the currency of Malawi: Malawi Kwacha (MWK) is not in the list of currencies in number formats.
1 MWK = 100 tambala (but tambala are rarely used)
Please see: http://en.wikipedia.org/wiki/Malawian_kwacha
Currencies are part of LibO locale data, we could benefit from a set of ny_MW locale data. ny_MW because we already support Nyanja in the language list, assigned to the ny_MW locale. For how to contribute locale data please see https://wiki.documentfoundation.org/LibreOffice_Localization_Guide/How_To_Submit_New_Locale_Data
Of course it's not necessary to create yet another issue in Bugzilla, as the wiki page suggests, just attach the data to this issue when ready.
Instead of ny_MW also en_MW could be used if we added English_Malawi to the language list, as English is an official language of Malawi according to http://en.wikipedia.org/wiki/Malawi, that may be easier than having to come up with Nyanja localization of calendar items and such ... If that's sufficient just leave a note here, I'll inherit en_MW from en_GB then and do the necessary changes.
Thanks Eike for your response.
I have just spoken today with someone from Malawi how to deal with the Malawi locale. The vast majority of people using computers is speaking English, so en_MW would be the way to go. It would be great if you could inherit en_MW.
By the way, the local language is officially referred to as Chichewa in Malawi, although the locale code ny_Mw is correct.
Eike Rathke committed a patch related to this issue.
It has been pushed to "master":
fdo#48111 added English_Malawi [en-MW] locale data