The discussion focuses on simplifying the square root of 72, demonstrating that √72 can be expressed as 6√2 by factoring 72 into a product of a square number (36) and another integer (2). This technique is known as simplifying a square root. The term 'surds' is used in textbooks to refer to square roots of integers that cannot be simplified further. The process involves breaking down the square root into its constituent parts to make calculations easier. Understanding this technique is essential for working with square roots in mathematics.