Developing students' reading and numeracy skills remain key goals of contemporary schooling. In Australia, the National Assessment Program -- Literacy and Numeracy (NAPLAN) tests have assessed these skills since 2008. Previous research found a significant gender gap in favour of females for the NAPLAN writing test, yet no study has examined whether gender gaps exist for reading and numeracy or their developmental pattern across the school years. Given the educational and public interest in NAPLAN and its considerable costs, it is important to understand what these tests reveal about student outcomes. The paper presents the first investigation of patterns of male and female student achievement on the NAPLAN reading and numeracy tests from 2008 to 2021. It applies the equivalent year level technique to explain the pedagogical significance of NAPLAN achievement and compares the findings with the writing gender gap to present a fuller picture of male and female achievement.