in luxembourg mexico and the netherlands the promale gender gap shrank because boys performed more weakly while girls stayed steady however comparisons between the performance of yearold students in oecd pisa in and the performance of roughly the same birthcohort at around age in the oecd survey of adult skills piaac suggest that gender gaps in mathematics sometimes widen as teenagers move into adulthood figure among oecd countries with available data the average standardised gender gap is points at the age of and points at around age still only small however in canada austria and norway the standardised gender gap among those aged around is greater than points and in finland and the united states it is larger than points figure