Thats incorrect (in the article). The words are compound words, and they really should not be counted like they are here.

example:

chauntees = 34 = 30 and 4. Word for 30 is tees and word for 4 is char - combined to form chaun-tees.

chhuttees = 36 = 30 and 6. Word for 30 is tees and word for 6 is chey - combined to form chhut-tees.

So on for all the words from 20 till 99. The combination rules might not be obvious here in transcription, but they come naturally to a Hindi speaker. So in reality there are dedicated words for 1 thru 19, and then the rest are compounds formed from the words corresponding to each digit.

(Native Marathi, competent Hindi speaker here. Marathi has the same problem)

So, it's not like each number has a different name.

However, it's almost like that.

Basically, the numbers can be broken down into a logical tens and ones place -- e.g. 45 will be five-forty (paintalees -- pai/talees), however the exact way to say "five" will change based on the number, as will the exact way to say "forty".

There's not much logic to it -- some tens series are more regular than others -- which means you effectively end up memorizing it, but subconsciously.

Imagine numbers in English but there were three ways of saying each digit, and each number 1-100 would pick from the synonyms. It's basically like that. That is to say, it's not too hard to deal with -- you'll mentally be associating the numbers with their words so it's not hard to say it out, and because they're synonyms not hard to understand when spoken.

Every number doesn't have its own name. If you observe closely there is a pattern. From 21 to 99, you can observe that every digit at tens place decides the suffix and the digit at ones place decides the prefix.

Further, the author says "because of a lot of irregular pronunciation, you have to memorize 100 different words as if it were a centesimal system". But I could say the same for English. We won't say "three-ty-three", we say "thirty-three". Hindi's irregularities are pretty much at the same level.

No, for English the thirty series is always "thirty-foo", and numbers ending in three are always "foo-three". It is true that you don't use the same word for the number when it's in the tens place (like Chinese), but that's as complex as it gets (and the teens, of course).

In Hindi 40 and 41 use a different word for 40. 51 and 53 use a different word for 50. 55 and 45 use a different word for 5. Plus there are smaller but still significant differences between pretty much every number -- e.g. it's chauBees, but puchees and chauNtees.

I am not a native Hindi speaker by any means, and I certainly haven't done math in it. But my experience (in places like Delhi) is that people routinely use Hindi up to 20, then give up and switch to English.

This is only true for young urban middle class people.

Yeah, my sample is fairly biased in that direction. That and rickshaw wallahs who'll speak the language of their market I guess.

It's not that difficult. The names are different but they "make sense". It's like 'fifteen', 'sixteen' and 'seventeen' stretched up to 100. Different names, but the pattern is sort of obvious with a few exceptions here and there.

I am a native Hindi speaker and I don't think Hindi is very different from base-10 number system(as the article acknowledges) thus there shouldn't be any difficulty as such. Although I can't say that I have done any kind of mathematical calculation in Hindi script/numerals ever.

NOTE: Hindi has its own script for numbers as well which the article is missed to point out.