The figure was revealed at a conference last week to mark International Literacy Day. The occasion was also the launchpad for a new set of Big Plus advertisements to help promote awareness of the problem.
Allan Wilson, the Deputy Lifelong Learning Minister, told the learndirect scotland ceremony that the number who have now received help would have filled the old Hampden Park at the peak of its capacity.
An estimated 23 per cent of adults in Scotland - 800,000 people - have low literacy and numeracy skills. Some 500,000 of these are said to be in work.