Learning cards set provides a variety of ways to let your students practice & reinforce important math skills. Grade-level appropriate math problems help students develop a better understanding of subtraction. Double-sided cards provide a perfect way for students to practice subtracting numbers horizontally & vertically, whole numbers, single-digit numbers & double-digit numbers. Cards are compatible with the Teacher Created Resource Power Pen (sold separately) for immediate feedback with an audio & visual response. Set is designed for children attending kindergarten to second-grade.