Engineers wield various "calculi" to help determine solutions to their problems, calculation tools varying in power from tensile strength tables to the differential calculus. A calculus is normally based on induction over an algebraic structure. Here I explore how architecture styles can be used to describe such structures. An example calculus based on an "integration" style is presented, which is intended for use as a sub-style of other architecture styles. Calculation rules in terms of the architectural elements can be used to compute non-functional attributes of artifacts described in such styles. Naturally, computerized support for calculi will help to automate the tasks of software engineers.