Convert Numbers spreadsheet to microsoft excel spreadsheet

[Edwin1]

I am using Numbers on my IMac, and I need to convert a Numbers spreadsheet to a Microsoft Excel spreadsheet. I have LibreOffice loaded on my IMac.

[ROSt53]

Please have a look at:

How to transfer spreadsheet from Apple Numbers to LO Calc?

A friend has a spreadsheet (with single worksheet) in Apple Numbers, which he wishes to send me to use in LO Calc. What is the best format for him to send it to me in? I have LO 3.5.7.2 under Windows XP; he has Mac OS X 10.5.8, Numbers '09 version 2.0.5 as part of iWork '09 package version 9.0.3.