Maths grades at higher level showed a marked improvement this year.
However, IBEC, the employers' body, expressed alarm at the sharp rise in failure rates at ordinary level. "It is simply unacceptable that over 16 per cent of ordinary-level students have not achieved a pass in this subject," said IBEC's assistant director, Ms Aileen O'Donoghue.
The number of As at higher level rose to almost 21 per cent, one of the highest levels recorded in recent years. Last year 14 per cent received an A grade and 17.4 per cent the previous year.
The number getting A1s this year rose from 7.1 to 11.4 per cent. An A1 grade is worth 100 points, and DIT and the University of Limerick give extra points for reaching this level.
Higher-level maths is traditionally regarded as one of the toughest subjects in the exam, but based on this year's marks students have a far higher chance of getting an A grade in maths than in Irish or English.
The number of honours grades generally in maths was also up from 74 to 80.5 per cent.
The failure rate was down from 4.9 to 4.1 per cent.
At ordinary level the picture was radically different, with failure rates rising to 16.7 from 12.7 per cent. The number of honours grades also dropped from 66 to 62 per cent. The number of A grades dropped from 14.4 to 14.1 per cent.
The students who failed the subject will find difficulty getting places in many third-level courses and possibly securing employment.
More than 11,000 students took maths at foundation level, while almost 10,000 did so at higher level.