Learn English – How to say in one word “number written in words”

In the UK, we always put the "and" in after the hundreds in plain numbers. Commas appear to be put after every "power of 1000" term ("thousand", "million", "billion" and so on); I'm not sure whether that's a requirement or just a good idea. However, not even the most knee-jerk believer in Oxford Commas would put a comma after the hundreds. So it is:

One thousand, two hundred and ten.

In the US, they seem to always leave the "and" out, but use commas in the same way:

One thousand, two hundred ten.

There is another alternative, though. With a number like this between one and two thousand, in the UK at least we might still talk about it hundreds:

Twelve hundred and ten.

This is very much dependent on context and personal preference, but it does happen so you shouldn't be surprised by it.

"One hundred and thirty-five" is perfectly correct, although the "and" tends to be removed in American English. It makes sense mathematically, since "and" is synonymous with "plus" — two apples and three apples makes five apples. One hundred, and thirty-five, makes 135.

The "and" is particularly useful when articulating a series of numbers. "One hundred one, one hundred two" could easily be misheard as "one hundred, one, one hundred, two" whereas using "one hundred and one, one hundred and two" removes that ambiguity.

Ultimately though it depends on location and culture. In the UK the "and" is always used; in the US there are a mixture of usages.

Looking at this ngram, it seems that skipping the "and" has only gained popularity over the last hundred years or so but using the "and" is still far more prevalent: