What is the pigeon hole principle, the sixth grade mathematics education edition?
From 1 to 10, arbitrarily select six numbers, and the sum of the two numbers must be 1 1.
Tell me the principle.
We divide 1~ 10 into five drawers according to (1,10) (2,9) (3,8) (4,7) (5,6), so if we take 6, we will definitely get two numbers of at least one drawer.