TREND enterprises, Inc. Reading Power Pack Self-checking flash cards feature answers on back for independent learning. Great for school, home, childcare, and travel. Durable, no-see-through cards. Quick-sorting, rounded corners. 56 two-sided cards, 3 1/8" x 5 1/4". Great for school, home, childcare, and travel. Durable, no-see-through cards. Quick-sorting, rounded corners. 56 two-sided cards, 3 1/8" x 5 1/4".