A Bond Math (Section 7, Question 2, "Circumference and Area of Shape", Summer School for Grade 4 to Grade 5) Olympiad Math Problem.

1, the area of each square is 400÷ 16=25 square centimeters, and the side length is 5 centimeters;

2. The sum of the perimeters of the16 square is 5× 4×16 = 320 cm;

3. All other 14 squares have two sides overlapping (that is, 14 squares have two sides subtracted: 5× 2× 14).

4. The circumference of this graph is: 320-10-140 =170cm.

Another kind:

It is known that the "5" of a square with a side length of 5cm 16 becomes a rectangle after stretching.

The length is 5×16 = 80 cm; The width is 5 cm; So the circumference is:

(80+5) × 2 = 170cm