Practice calculus with this solutions manual For students using Calculus: One and Several Variables for classroom instruction, this complete solutions manual for chapters 1-12 provides the answer key to the one-variable problems presented in the text. Now in its tenth edition, Calculus: One and Several Variables has become known for its easy-to-understand writing style and balance of theory and application. With this solutions manual, students can apply their knowledge using the problems presented in the first 12 chapters and check their work as they go.