The president of the Primary Maths Association of South Australia said there was "no uniformity" in the marking criteria across and within the states and territories, and between state and private schools.
According to the Flinders News, Lisa-Jane Connor suggested private students were getting higher marks than public school students who did work of a similar quality.
"This could mean that a B grading is awarded in a private school for work that attracts a D grading in a public school," the paper reported.