Unifix cubes are a concrete representation of addition/number bonds. Building the bond with the Unifix cubes is what develops number sense. Great use for flash cards instead of looking for just memorization
Place Value Practice - Numbers 11 to 29 - Freebie - Students use their knowledge of place value, ten frames, and counting skills to fill out these useful number sense worksheets. Ideal for Kindergarten or First Grade.
Apple Unit from Kindergarten Hoppenings / Great when teaching seasons. Could use balls of tissue paper for each season, and have each student glue one piece onto each tree. so the whole class makes ones poster together