These inexpensive tangram puzzles are made out of solid wood tiny blocks to develop confidence in improving psychological quality. Math Kangaroo (MK) Tangram Puzzle provides valuable entertainment for age 8 to 100 yeas old! Includes a booklet listing 18 challenges. That was the gift for each of MK participants in the past. Dimensions: 4.5 in by 4.5 in by 0.5 in. Buy this set for $4.99 plus shipping or enjoy free shipping when you purchase 5-pieces-pack or 15-piece-pack or 25-piece-pack(for all your class!