Student or Learner
"We had agreed the event would take place in 2010, from October 10 to 22."
Would it be better to write "from October 10th to 22nd"?
It's up to you. You version is clear enough. My own preferences are for 'We had agreed the event would take place from 10 to 22 October 2010' or 'from 10-22 October 2010'.