A learning aid which can be implemented in computer software where a user's responses to a timed worksheet are used to adjust parameters used in selecting the problems and time limit in a successively timed worksheet. Parameters can include problem complexity, the mode or type of problems having a given complexity, the number of problems, worksheet time limit, and measures of user performance including time remaining and the number of correct, incorrect and non-completed answers to problems. Performance is tracked over successive worksheets in order to arrive at a user's competency level and to provide the user feedback tailored to enhance the learning experience.