Six coins for fortune telling

No, just three. There are four changes in front and back after throwing. The front is marked with the number "3" and the back is marked with the number "2". Add up the three numbers, and the number range is 6789. Seven and nine are marked "-",and six and eight are marked "-". In this way, six permutations are thrown from bottom to top, and one of the sixty-four hexagrams is obtained. Just refer to the Book of Changes and look it up.