Concept:The Pascaline, invented by Blaise Pascal, is an early mechanical calculator built around counting wheels.Explanation:Its mechanism directly supported addition and subtraction.Multiplication and division were not performed directly by the machine's primary design.Such operations could only be attempted through repeated addition or subtraction, making them inconvenient.Therefore, the Pascaline was practically useful for addition and subtraction only.Answer:A. addition and subtraction only.