Problem
COM-B1-M05-P002 Same Last Digit
#2
★☆☆☆☆ Level 1 of 5
Prove that among any \(11\) integers, two have the same last digit.
There are only \(10\) last digits.
The boxes are last digits \(0,1,\ldots,9\). There are \(11\) numbers, so two fall into the same box.
Residues modulo \(10\).