This paper investigates the possible influence of attitude on seven Year 11 students' use of a Computer Algebra System (CAS) during a class activity where students could choose to use CAS or pen-and-paper in solving a range of problems. Investigation of anxiety, confidence, liking and usefulness through a survey and interview revealed that these components of attitude could influence whether or not a student chose to use CAS. One student, who had a positive attitude towards CAS, made extensive use of CAS in solving given problems. This suggested that, in this case, the student's positive attitude towards CAS may have positively influenced her use of CAS. The potential impact of attitude on CAS use has implications for students studying in a school system where CAS is expected to be used in mathematics.