is it wrong to say (as a grammar book says) that you have 2 pairs or 3, as the case in plural may be, of shoes or whatever? Is 'I have 3 pairs of shoes' wrong, grammmatically?
To me it seems perfectly ok.
noun, plural. pair or pairs.
USAGE NOTE After a number other than one, pair itself can be either singular or plural, but the plural is now more common: She bought six pairs (or pair) of stockings.
paired: Definition, Synonyms and Much More from Answers.com