The sum of 3 consecutive natural numbers, the first of which is n.
We have 3 numbers:
n, n + 1, and n + 2
Add them up:
n + (n + 1) + (n + 2)
Group like terms:
3n + 3
We have 3 numbers:
n, n + 1, and n + 2
Add them up:
n + (n + 1) + (n + 2)
Group like terms:
3n + 3