This discussion features an excel formula that converts a given number into words. No VBA required, just functions. It is noteworthy that the formula (although, a pretty messy one) makes use of special functions such as LET and IFS. It does not support… More on learn.microsoft.com

The "optimum" is different for everybody, unfortunately. Some people struggle at 20 per day, while some people can do over 100 and retain all or most. I'd start high and keep up regularly with your reviews, and if you're struggling then lower it a bit at a time until it becomes doable (or if it's too easy, raise it a bit until you start to sweat a little). Here are some tips for raising your number of words: I would recommend reviewing new words several hours later or shortly before bed on the same day if you can. This helps solidify them more in your memory. Don't leave your first review for the next day if you can avoid it, basically. Taking frequent short breaks in your studies can also be extremely helpful for retaining large amounts of information. Every 15 minutes take a 5 minute break and get up and walk around, do some stretches, maybe play a quick casual game; anything to snap you out of the studying mindset. People tend to remember the first and last things they encounter in a study session the most vividly, so if you take frequent breaks you'll get a lot of this bonus ;) Music can also be really helpful to cement things in your long-term memory. People can often even remember the lyrics of songs they haven't heard in over a decade! Look for songs with the words you're studying in the lyrics. Even if you don't understand most of the lyrics of the song yet, at least learn the line that has the word(s) in it as well as its translation. Every time you hear or think of that song, you'll remember the word(s)~ Edit: the link u/Maxfjord posted has some good tips, too~ More on reddit.com

The number program (in the bsdgames package on most systems) does this already.

Remember the story of the 10,000 lines.

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Fluent speakers have a passive vocabulary of roughly 20,000 words and an active one of roughly 5,000 words. Only very educated native speakers go much above that. If your goal is to be considered a native speaker of German, you need to drill the noun genders like a maniac. Foreigners, regardless how fluent they are in German, and how accent-free they speak, typically make at least ten times more gender errors than native speakers. We are talking about one out of a hundred nouns used vs one out of a thousand nouns used here. We use that telltale sign to spot the foreigners as German dialects and their accents differ wildly, and what may sound like an English accent may be a Frisian one. More on reddit.com