1: perimeter of primary school mathematics 2 learning objectives: 1 knowing perimeter 2 learning the formula of rectangular perimeter of a square, doing rectangular and square perimeter questions. Difficult knowledge: square rectangle perimeter formula. 3 the process of deriving the formula of right-angled square 4 the formula of square circumference: side length x four four

Rectangular formula: (length+width) x2 5 Make a rectangle, a square and a perimeter. 6 Xiaoming's father bought a rectangular water tank. He wants to measure the circumference of the water tank. Its length is 3㎝, and it is 6㎝. Could you please find out the circumference of Xiaoming's father's water tank? (4 points) 7 Kobanawa Xiaohong made a square paper tube in the competition. Halfway through, Xiaohua said what is the side length of this square paper tube? Xiaohong said that the circumference of the square is 16㎝. Children, can you help Kobanawa Xiaohong find the side length of a square paper tube? (5 points) There is a new square washing machine and a rectangular refrigerator in the mall. Rectangular refrigerator length 1000cm, width 18m, side length of square washing machine 128㎝. Is the circumference of a rectangular refrigerator less or more than that of a square? More or less? (8 points) 9 Xiaohong bought a rectangular medicine and a square Banlangen? The rectangular cold medicine is 999cm long, and its width is 9 squares smaller than its length. The side length of square isatis root medicine is much longer than that of rectangular cold medicine 12 square. What is the circumference of rectangular cold medicine and square isatis root medicine? (10)