1, outermost number:

① Number of people per side × 4-4

Count the four corners again, so you have to subtract 4.

② (number of people per side-1) × 4

Dividing the outermost square into four identical parts can also be understood as the problem of finding the number of segments by recycling trees.

2. Total number of people in the phalanx: number of people on each side × number of people on each side.

Third, examples.

Xiao Ming uses several pieces to make a square, with 6 pieces on each side of the outermost layer.

(1) How many pieces does it take to form such a square?

(2) What is the total number of the outermost pieces?

Solution: (1) 6× 6 = 36 (pieces)

(2) 6× 4-4 = 20 (piece) or (6- 1)×4=20 (piece)