Problem #PRU-65387

Problems Methods Colouring Chessboard colouring Examples and counterexamples Pigeonhole principle Pigeonhole principle (finite number of poits, lines etc.)

Problem

What is the minimum number of \(1\times 1\) squares that need to be drawn in order to get an image of a \(25\times 25\) square divided into 625 smaller 1x1 squares?