A considerable number of children rely on counting to solve single-digit addition problems when they are expected to use accurate retrieval-based strategies. There are different reasons why this may be so. Children may use inefficient counting strategies, produce errors when applying backup strategies or lack sufficient confidence to just state the answer. In this study, children in Years 2-6 (n = 94) were assessed on how the solved single-digit problems. Data were analysed to identify five performance groups that represented different patterns of difficulty. The findings highlight how interventions need to be better tailored to suit individual learning needs and indicate how this may be achieved.