We present a practical algorithm for computing least solutions of systems of (fixpoint-)equations over the integers with, besides other monotone operators, addition, multiplication by positive constants, maximum, and minimum. The algorithm is based on max-strategy iteration. Its worst-case running-time (w.r.t. a uniform cost measure) is independent of the sizes of occurring numbers. We apply this algorithm to the problem of computing the abstract semantics of programs over integer intervals as well as over integer zones.