This is supported by Cohen et al who state that "children's characteristics go beyond their simple learning preferences and include, for example, their interests, their self-concept, their motivation, their degree of learning. autonomy” (2004, p. 137). Furthermore, O'Brien and Guiney (2001 p. 11) argue that diagnosing learner performance arises from very complex interactions and define differentiation (p. 10) as a concept that must be viewed inclusively and applied to everyone. It was with this in mind that a mathematics teacher, observed teaching the upper and lower groups (the better English and the weaker English), designed her lessons. Despite the fact that each group was relatively homogeneous in terms of English language proficiency, both groups were mixed ability groups according to the characteristics described by Cohen et al (2004, p. 136). In both classes, the teacher was observed using various differentiation strategies such as pair work, group work, and peer assessment. After setting the tasks, it was also observed that the teacher gave more individualized attention to the weaker learners and more independence to the stronger ones. Additionally, when a student needed help while the teacher was busy helping another student, the teacher often assigned a stronger learner to help their peer. By having a stronger one to help one