1 The use of "and" in numbers.
An easy definition
"And"
is put between hundreds and tens.
A complete definition (to my knowledge)
A three digit number, comprised of hundreds tens and units, will hereby be referred to as a category.
i.e.
in the number 123,456,789
123 = million category
456 = thousand category
789 = hundred category
For
learners of the English language
1,4 and 7 = hundreds
2,5 and 8 = tens
3,6 and 9 = units
When a category is divided by 100 and there is a modifier, "and" is put before the modifier.
2 The use of a "hyphen".
An easy definition
A "hyphen" is put between tens and units.
A complete definition may be possible on request.
3 In ordinal numbers
When the number is 100 or more, the last word is written in ordinal form.
(The other words remain cardinal. When less than 100, it is regarded as a word.)
日本語のルールは後日掲載の予定です。
参考文献
銀林浩・銀林純著「基礎からわかる数・数式と図形の英語」日興企画
OXFORD Advanced Learner's Dictionary: 5th edition.
ルールについては、自分で「定義」？してみたあと、ネイティブにチェックしてもらいました。
（3. In ordinal numbers.については「基礎からわかる数・数式と図形の英語」とほとんど同じになってしまいました。）