Writing numbers properly can be tricky. There are a few things to keep in mind.
Remember that you should use a hyphen only in compound numbers between 21 and 99. Don’t use a hyphen when numbers are greater than 99. So you should write:
- thirty–three
- one hundred and thirty–three
- five thousand and seventy–nine
You should not write:
- seven-hundred
- one-hundred and thirty-three
- five-thousand and seventy-nine
Those hyphens are incorrect because they appear in numbers greater than 99.
The use of “and” is also tricky. In British English we always use “and” between hundred/thousand/million/etc and numbers below 100. As in:
- seven hundred and five
- two million and ten
- six thousand, five hundred and nine
In American English it is acceptable to omit “and.” As in:
- seven hundred five
- two million ten
I wonder, though, if the British “and” is becoming more common among American speakers and writers.