Take 3 consecutive numbers, e.g. 5,6,7.

- Square each one.
- Add the 3 squares.
- Subtract 2 from the sum.
- Divide the result by 3.
- Write down number.

- Take 3 other consecutive numbers 10, 11, 12 & repeat.

- Predict answer for 19, 20, 21.

- Using
n,n+1,n+2simplify and show how this pattern works.