What is the algebraic expression for the sum of three consecutive integer?
Sum of three consecutive integer number is 3 times the middle value: That is 3n given that the mean number is n.
Let any integer number be n
Then the number 1 less than it is n-1
Also the number 1 more than it is n+1
So the sum is
Adding these we have
So the final sum is
Note: the mean value is