CONSIDER THE NINE NUMBERS 1!, 2!, 3!, 4!, 5!, 6!, 7!, 8! AND 9!. W...

6. - ĐỀ THI OLYMPIC TOÁN TMO VÒNG CÁ NHÂN
Toán ĐỀ THI OLYMPIC TOÁN TMO VÒNG CÁ NHÂN

6.

Consider the nine numbers 1!, 2!, 3!, 4!, 5!, 6!, 7!, 8! and 9!. What is the

maximum number of them we can choose so that the product of the chosen

numbers is the square of an integer?

Answer :