This activity comes with downloadable engineering challenges and optional labs. For ages 5 through 13 (different challenges/labs for different ages). Optional activities teach about fractions, ratios, proportions and mechanical advantage. Class Pack Includes 20 x Hole Plates 20 x 50 Tooth Gears 20 x 40 Tooth Gears 20 x 20 Tooth Gears 20 x 10 Tooth Gears 100 x Dowels 100 x Perpendicular Blocks 20 x Connector Strips 10 x 3in Slide Stop The Maker Tool Set (9T-182384) is required for construction.