This study involved 34 female adolescent students attending mathematics classes in a girls' hostel in Hong Kong. The subjects' ages ranged from 12 to 18 years. All students exhibited varying degrees of emotional and behavioural problems, and all experienced learning difficulties in mathematics. The study aimed to discover whether the use of a simple token reward system would increase the students' work output, participation rate, accuracy, and neatness of bookwork during mathematics lessons, and whether the system would also have a positive influence on the girls' attitude toward mathematics. The four-week intervention programme involved the provision of token rewards during lesson time to every girl who showed any improvement in any of the four aspects of learning. Baseline measures were taken over a two-week period before the intervention commenced, and regular measurements were taken during and immediately after the programme. The same measures were taken again four weeks after the reinforcement programme had ended to check for maintenance. The results showed that the use of tokens did lead to significant improvements (in most cases p <.01 or better) in work output, participation rate, accuracy and neatness while the programme was in operation. Performance declined, however, in all but neatness once the tokens were no longer in use. The decline in scores did not regress to the baseline level, but most differences were no longer statistically significant. Very minor attitudinal changes in a positive direction were noted; but only in one case did these reach statistical significance. [Copyright of Hong Kong Special Education Forum is the property of Special Education Society of Hong Kong Ltd.. Full article may be available at the publisher's website: https://sites.google.com/a/seshk.org.hk/seshk-org-hk/c_publication]