Teacher-created, child-tested flash cards are ideal for reinforcing basic subtraction skills at home or school. Handy 3-1/8" x 5-1/4" size makes cards great for travel. Rounded corners allow quick sorting. Set of 56 Subtraction Pocket Flash Cards includes activity ideas to challenge growing skill levels. Cards are ideal for teaching students in first-grade to second-grade and ages 6 to 7.