You can achieve such a numbering scheme with two fields, coded as:
{={PAGE}*2-1}
and:
{={PAGE}*2}
for the left and right-hand numbers, respectively.

Note: The field brace pairs (ie '{ }') for the above example are created via Ctrl-F9 - you can't simply type them or copy & paste them from this message.

__________________
Cheers,
Paul Edstein
[Fmr MS MVP - Word]