I see this a fair bit in journal papers, and wanted to know if there is a specific reason and/or term for this: having the spelled/lexical version of a number followed by the literal/logical representation. An example would be:
A fifty (50) caliber round can penetrate conventional armor.
Why is "fifty" trailed by "50", and what is the purpose? I can imagine this in translation documents or multilingual documents, but I'm confused why this is common practise in various papers, instruction manuals, etc.