This presentation reports on a study on upper secondary school students’ opi-nions and views regarding an online enrichment in mathematics. Interviewswere conducted with seven participating students, who express that the enrich-ment deepened their mathematical knowledge, in line with the fact that learn-ing requires challenges. They enjoy to always have a challenge to work on andalso freedom to decide when to work on it, which connects to the description ofmathematically highly able students as autonomous. Several students explicitlypoint out that they like that the work was not graded. Students differed in termsof working alone or with peers. The online enrichment offered mathematicalchallenges for most students, but some would have liked even more difficulttasks. Their involvement differed depending on other school work.