The main arguments in this paper are that management control succeeds because it fails, that it fails because it succeeds, and that accounting numbers work because they are problematic. It is when accounting succeeds in gaining support of powerful allies, silencing other voices, and appears as immutable; a conveyor of truth, it undermines the activities it is supposed to represent and control. When accounting fails to convince, however; when it produces ambiguity, fails to speak for everyone, and makes up a contestable element in the fabric of reality, it contributes to new problematisations, new solutions and new activities. These claims can be made by complementing earlier analyses of management accounting and control with recent writings on multiple practical realities, fluid technologies, and mattering. The analysis of this paper shows that the power to control matters does not necessarily lie in the ability to handle or control certain kinds of matters, such as inscriptions. Instead there are always on-going struggles over controlling the mattering practices that keeps the world going.