This is a set of 3 Kodomo Challenge workbooks. Comprehensive Workbook: For ages 4, 5, and 6. Retail price: 880 yen. Numbers ③: For ages 4, 5, and 6. Retail price: 880 yen. Thinking ③: For ages 4, 5, and 6. Retail price: 880 yen. I purchased these to prepare for school, but I didn't use them, so I'm selling them. They are unused, but have been stored at home. Please understand this before purchasing.