The circumference of a rectangle = (length+width) × 2c = (a+b) × 2; Perimeter of a square = side length × 4c = 4a; Area of rectangle = length x width s = area of ab square = side length x side length s = a.a = area of triangle = bottom x height ÷ 2s = ah ÷ 2; Area of parallelogram = bottom × height s = ah trapezoid area = (upper bottom+lower bottom) × height ÷ 2s = (a+b) h ÷ 2; Diameter = radius ×2 d=2r Radius = diameter ÷ 2r = d ÷ 2; Circumference = π× diameter = π× radius× 2c = π d = 2π r; Area of circle = π× radius× radius

Area of triangle = base × height ÷2. The formula s = a× h ÷ 2; Area of a square = side length × side length formula S = a× a'' Rectangular area = length× width formula S = a× b; Area of parallelogram = base × height Formula S = a× h.

Trapezoidal area = (upper bottom+lower bottom) × height ÷2 Formula S = (a+b) h ÷ 2; Sum of internal angles: sum of internal angles of triangle = 180 degrees. Cuboid volume = length× width× height formula: v = abh cuboid (or cube) volume = bottom area× height formula: v = abh cuboid volume = side length× side length× side length formula: v = AAA circumference = diameter× π formula: l = π d = 2π r.

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Judging from the mathematics learning psychology of primary school students, the learning process of students is not a passive absorption process, but a reconstruction process based on existing knowledge and experience.

Therefore, learning while doing and learning while playing will make children learn more actively. From our educational goal, while imparting knowledge, we should pay more attention to cultivating students' comprehensive ability of observation, analysis and application.