Sex Differences in Mental Strategies for Single-Digit Addition in the First Years of School

Strategy use in single-digit addition is an indicator of young children's numeracy comprehension. We investigated Danish primary students' use of strategies in single-digit addition with interview-based assessment of how they solved 36 specific single-digit addition problems, categorised as either 'error', 'counting', 'direct retrieval' or 'derived facts'. The proportional use of each strategy was analysed as multi-level functions of school age and sex. In a first study (260 interviews, 147 students) we found decreasing use of counting and increasing use of direct retrieval and derived facts through years 1-4, girls using counting substantially more and the other two strategies substantially less than boys, equal to more than 2 years' development. Similar results appeared in a subsequent study (155 interviews, 83 students), suggesting that the pattern is pervasive in Danish primary schools. Finally, we ask whether sex differences in strategy use is generally under-reported since many studies do not explicitly address them.