# Ordered papers

Author: mathforces
Problem has been solved: 26 times

Русский язык | English Language

Lin wrote six different numbers $a_1 < a_2 <... < a_6$ on six different pieces of paper. His friend Nil mixed them in such a way that they became ordered, that is, in ascending or descending order if one of the papers is not taken into account. How many such permutations exist?