HOW MANY SINGERS ACCOMPANIED THE ISRAELITES?

Ezra 2:65  Beside their servants and their maids, of whom there were seven thousand three hundred thirty and seven: and there were among them two hundred singing men and singing women. (KJV) Nehemiah 7:67  Beside their manservants and their maidservants, of whom there were seven thousand three hundred thirty and seven: and they had two hundred forty and five singing men and singing women. (KJV)

The author of Ezra was estimating, while the author of Nehemiah was giving the exact number.  An estimation is not an error, so this is not a contradiction.