Seven-year-olds are assessed by their teachers in national tests.
Fewer seven-year-olds in England mastered the basics of maths this year, according to government figures.
Some 89% of children met maths standards in their Key Stage One teacher assessments compared with 90% last year.
But the proportion of pupils meeting the level expected of them in writing rose by one percentage point to 81%.
Scores remained the same for speaking and listening, reading and science at 87%, 84% and 89% respectively.
The downward change in maths is only a small one but it will be a disappointment to ministers as early primary school results have bottomed out over the past two years.
The figures also show boys still lag behind girls in every area.
The difference is most marked in writing skills where 87% of girls reached Level 2, compared to 75% of boys.
Ministers have been targeting resources towards writing in a bid to tackle the underperformance of boys in particular.
But the latest figures still show one in four boys are unable to write at the expected level for their age.
In maths, 88% of boys reached the required standards, compared with 91% of girls.
However, there were gains among the brightest pupils.
Compared with 2008 the overall percentage achieving Level 2b in reading and writing increased by one and two percentage points to 72% and 60% respectively.
And the share performing at Level 3 or above rose one percentage point to 26%.
Schools minister Diana Johnson welcomed the results saying standards had remained high.
But added: "Those who do not reach the expected level must not be left behind. We are ensuring additional support will be available for those who don't hit the expected level including one-to-one tuition and increased support for children with special educational needs.
"And in maths, our Every Child Counts programme is giving intensive support to five to seven-year-olds struggling with numeracy and we are working with the Every Child a Chance Trust to help children to reach the expected level.
"This programme is already showing promising results with some children who have been on it showing progress at five times the expected rate."
General secretary of the Nasuwt teaching union Chris Keates said the results reflected the "upward trend in standards".
"Sustained and continued hard work and commitment by pupils and teachers is being rewarded," she said.
"These results demonstrate that pupils are being given a good start on their educational journey."