Catalog › Simple Machines (Step by Step Series gr 4-6) Image 1 of 1 Simple Machines (Step by Step Series gr 4-6) $7.00 Sold Out Using Simple Machines to learn about Force, Friction, work, power, and potential and kinetic energy. Sold Out Added! Using Simple Machines to learn about Force, Friction, work, power, and potential and kinetic energy. You Might Also Like Map Skills grade 2-3 (Creative Teaching Press) $12.00 You Can Draw Funny Animals $5.00 Fraction Wipe-Off Fun $5.00 Sold Out Wordsmith Craftsman $17.00 English and Grammar grade 3 (Skills for Scholars) $12.00