Current location - Training Enrollment Network - Mathematics courses - Mathematics talent in the second volume of the sixth grade
Mathematics talent in the second volume of the sixth grade
After any integer is divisible by 3, there must be three situations: divisibility, remainder 1 and remainder 2; Four integers, there must be two numbers divisible by 3 with the same remainder, so their difference must be divisible by 3.

It can also be explained by pigeon hole principle: there are three drawers, and the remainder divided by 3 is 0, 1, 2 respectively. Find any four numbers and put them in the drawer. At least one drawer has two numbers, and the remainder of two numbers divided by 3 is the same, so the difference can be divisible by 3.