They will say, "Three, the fourth is their dog." They say, "Five, the sixth is their dog," guessing at what they do not know. They say, "Seven, and the eighth is their dog." Say, "My Lord is fully aware of their number, none know them except for a few." So, do not debate in them except with proof, and do not seek information regarding them from anyone.
Translation endnotes
[18:9-27] These 19 verses contain numerous key words that strongly imply that the story of the cave have double meaning like the verses in chapter 74, and the second meaning is about a prophetic event. I have already observed examples of a hidden mathematical design, and God the most Wise will unveil it when the right time comes. When the secrets contained in the cave is revealed by divine permission, it will prove once again the truth in the assertion at 18:27. [18:22] The popular number, seven, is not the correct one. Also note that dog is treated as a member of the group, which contradicts numerous hadith reports that depict dog as animals to be shunned and even killed.