This study sought to determine: (1) what children understand about "chance" when they begin secondary school?; and (2) how common and how influential the use of informal heuristics, approaches, and biases is in their thinking about probability in the school context. Children's understanding of chance, attributions of events to influences, beliefs, and intuitions were explored. Interviews and questionnaires were conducted with 11- and 12-year-old children, eliciting their stories of chance, and focusing on the language of chance, including attributions and experience. Results were examined in terms of availability, representativeness, equiprobability, and C. Konold's "outcome approach." Religious beliefs, superstition, and language were shown to have significant influence on the children's thinking. Results support the need to facilitate the increased recognition and understanding of the heuristics and approaches commonly applied by children. (An appendix includes questionnaires which also list responses interpreted as "equiprobability" and as "representatives." Contains 18 references.) (BGC)