Mother asked me how to calculate the circumference of a square. I said loudly: side length × 4. My mother asked again: how to calculate the perimeter of the rectangle? I answered (length+width) × 2. My mother went on to say: If the side length of a square is 8 cm, please calculate its circumference. What if the side length of 4× 8 = 32 (cm) is 12 cm? I calculated 12× 4 = 48 (cm). The rectangle is 9 cm long and 5 cm wide. Would you please calculate its circumference? (9+5)×2=28 (cm) My mother praised me for my good mouth.