Question

Let n be the middle number of three consecutive integers. write an expression for the sum of these integers.

Answer 1

(n-1)+n+(n+1)
With n as the middle of 3 integers, n-1 is the integer just before n and n+1 is the integer just after n.

Answer 2

The expression for the sum of the three integers is 3n.

If n is the middle number of three consecutive numbers, then the number before n is (n - 1) and the number after n  is (n +1). By adding the three terms, we get an expression for its sum:$(n-1) + n + (n + 1)$. Simplifying the expression yields 3n. I hope this helps.