This article reports on two case studies in which we explored two Grade 6 teachers' mathematical knowledge for teaching the concept of the fraction. We were interested in the mathematical knowledge teachers need to have and are able to use to teach fractions. Of the two teachers who were observed and interviewed, one (Rose) explained the concept of the fraction by emphasising an understanding of mathematical concepts. She did this by using various modes of representation to teach the concept of the fraction and fractional manipulatives. On the other hand, the second teacher (Eddy) focused on procedural knowledge. Eddy used a traditional method to teach fractions, encouraging learners to memorise rules without necessarily understanding them. The learners followed the rules blindly because Eddy did not tell them how the rules originated.