In a numeral classifier language, a classifier (C) or measure word (M) is needed to link a noun (N) and its numerical quantifier (Num). This chapter first illustrates the confusions surrounding the convergence and divergence between Cs and Ms and offers some clarification. From the multiplicative mathematical perspective proposed in Greenberg (1990: 172), Au Yeung (2007), and Her (2012a), C and M converge as the multiplicand, with Num as the multiplier. Yet, crucially, a C’s value is numerical and necessarily 1, while an M’s value can be anything but 1, thus ¬1. An M’s value can therefore be numerical, for example, 2, 6, 12, and so on, or non-numerical, for example, kilo, meter, liter, bottle, and so on. This chapter then proposes a new and comprehensive taxonomy based on the different kinds of mathematical values encoded in C/Ms and further proposes a formal semantic account of this taxonomy.