Sorry Anonymous that I deleted your post by mistake, but here's the answer to the question:

"there are four posts on each side of a square fenced-in are. How many posts are there in all?"

The corner posts are counted for both of the adjacent sides.
So the total number of posts
= 4 sides *(4-1) posts
= 12 posts.

Draw a little diagram to make sure you understand the situation.

*..*..*..*
.         .
*         *
.         .
*         *
.         .
*..*..*..*

To find the total number of posts in the fenced-in area, you can follow these steps:

1. Visualize the square fenced-in area in your mind or draw a diagram of it. The square has four sides.

2. Recall that there are four posts on each side. However, when counting the posts at the corners, you need to account for the fact that they are shared by two adjacent sides.

3. Multiply the number of sides (4) by the number of posts on each side minus 1 (4-1). This will give you the total number of posts, considering the shared corners.

4. Calculate: 4 sides * (4-1) posts = 12 posts.

So, there are 12 posts in total in the fenced-in area.