This is a small collection of 3 math worksheets on the Calculus topic of derivatives. The worksheets provide instant feedback and fun for the math students because the answers correspond to letters or images that lead to the decoding of secret messages and pictures. They are also self-grading, which makes them ideal for customized treatment of learners. They are tested by multiple teachers, including the author and her colleagues. If you like these, you'll love "PUZZLE MATH: Trigonometry and Logarithms" also by Roxanne Eckenrode.