On-line quizzes are used to help first year University Mathematics students identify weaknesses in their basic skills and improve them. Quizzes developed as a formative tool have been utilised at JCU [James Cook University] for eight years. However, before this research no-one has questioned the effectiveness of quizzes for this task. We present a description of the quizzes used in a core first year Mathematics subject at JCU and provide a statistical overview of their usage and efficacy for the intended task.