A survey of nearly fifteen hundred General Certificate of Education Ordinary Level (GCE O‐level) answer papers selected from eight countries was carried out and the erroneous answers to selected questions were recorded. Amongst those questions examined was one which concerned probability, and the findings are reported here. When the question involved a single event the success rate of the candidates was high, but as soon as the situation involved a multiple event the success rate was very low. A number of erroneous strategies were noted to alert researchers to the need to discover their root cause.