HOW MANY LEVITES WERE THERE?

Number 3:39 All that were numbered of the Levites, which Moses and Aaron numbered at the commandment of the LORD, throughout their families, all the males from a month old and upward, were twenty and two thousand. The text is too long to copy in here, but Numbers 3:17-38 give the subtotals for each family add up to 22,300, a difference of three hundred from the grand total given in 3:39.

It's possible the number given in 3:39 was an approximation (and an approximation is not an error), or it's also possible that the '300' (which is a single character in Hebrew) was in the original text, but was later dropped due to a transcription error.  Either way, there were no errors in the original text, so this is not a contradiction.