> even in the sum example, you see the statement "N is n-1" That wasn't actually what the example said. It said N1 = N - 1, and continued using the N1 value so

> even in the sum example, you see the statement "N is n-1" That wasn't actually what the example said. It said N1 = N - 1, and continued using the N1 value somewhere else. In that example, no actual mutation occured.