Please note I have had permission from S&S to add links to my website to the answer books: Book 2: https://www.schofieldandsims.co.uk/downloads/MentalArithmetic/mental-arithmetic-2-answers.pdf Book 3: https://www.schofieldandsims.co.uk/downloads/MentalArithmetic/mental-arithmetic-3-answers.pdf Book 4: https://www.schofieldandsims.co.uk/downloads/MentalArithmetic/mental-arithmetic-4-answers.pdf Book 5: https://www.schofieldandsims.co.uk/downloads/MentalArithmetic/mental-arithmetic-5-answers.pdf Book 6: https://www.schofieldandsims.co.uk/downloads/MentalArithmetic/mental-arithmetic-6-answers.pdf