Originally Posted by

**Veronica1999** 1. A flat, rectangular board is built by gluing together a number of

square pieces of the same size. The board is m squares wide and n

squares long. Using the letters m and n, write expressions for

(b) the total number of 1 × 1 squares with free edges (the number of

1 × 1 squares that are not completely surrounded by other squares);

I just doubled the perimeter 2(m + n) and then subtracted 4 to correct the overcounting.

Teacher says I am missing the point of the problem and should have done

mn - (m - 2)(n - 2) = mn - mn - 2m - 2n + 4

Whats wrong with getting it simpler?

Nothing wrong, in my opinion ... some teachers prefer you do it their way.

What is the point of the redundant way?

???