Digital talking books have been developed to enhance reading experiences for reading-disabled people. In the existing digital talking books, however, it is difficult to read special contents such as math expressions, images, etc. In this paper, we define reading rules for Contents MathML. Based on this rules, we implemented a program for reading the mathematical contents of Contents MathML, using XSLT. We conducted a confirm test to prove the accuracy of the program, and an usability test to measure understanding of reading text of math expressions.