The relationship between mathematics and spatial reasoning is well established and extensively researched. Certain mathematics content could be deemed explicitly spatial, for example within geometry. However, the link to spatial reasoning extends into other areas of mathematics, such as representations of the number line and reading and interpreting graphs. Correlational and training studies have tended to focus on mathematics either broadly (e.g., standardised test scores) or with specific measures (e.g., arithmetic) when examining the relationship between mathematics and spatial reasoning. In the present study, 455 students from grades 4 through 9 completed digital assessments of mathematics and spatial reasoning. The mathematics tasks reflected curriculum content with varying degrees of spatial intent. Separate assessments were developed for the primary and secondary cohorts. Relationships between mathematics task performance and spatial reasoning indicate distinctions in problem-solving between item types with different spatial skills influential for different content. The role of spatial reasoning in interactive forms of digital assessment is discussed.