Actually, the students are demonstrating profound depth. They recognize that 4+3+2 is an expression, 7+2 is an expression, and the two may evaluate to the same number in Peano arithmetic, but they are not identical expressions, i.e. don't satisfy a deep equality test. They resolved the confusion by inventing a novel inflationary Fibonacci algebra, where by definition x + y = (x + y) + y = (x + 2y) + y = ... They ran out of room on the test, so terminated the series and reverted to the boring conventional notion of equality. I ran the numbers and discovered that inflationary equality in fact is the missing piece of a GUT that describes the fundamental structure of the universe.