Area of triangle = base × height ÷2. The formula S=a×h÷2? Area of a square = side length × side length formula S=a×a? Area of rectangle = 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

Volume of cuboid (or cube) = bottom area × height formula: V=abh? Volume of cube = side length × side length × side length formula: V=aaa? Circumference = diameter × π formula: L = π d = 2π r? Area of circle = radius × radius× π formula: s = π R2.

Surface (side) area of cylinder: The surface (side) area of cylinder is equal to the perimeter of bottom multiplied by height. Formula: s = ch = π = 2π RH.

Surface area of cylinder: the surface area of cylinder is equal to the perimeter of the bottom multiplied by the height plus the area of the circles at both ends. The formula S=ch+2s=ch+2πr2.

Volume of cylinder: the volume of cylinder is equal to the bottom area multiplied by the height. Formula: V=Sh? Volume of cone = 1/3 bottom× product height. Formula: V= 1/3Sh

Law of fractional addition and subtraction: Fractions with the same denominator are added and subtracted, only the numerator is added and subtracted, and the denominator remains the same. Fractions of different denominators are added and subtracted, first divided, then added and subtracted.

The multiplication of fractions is: use the product of molecules as numerator and the product of denominator as denominator.

The law of division of fractions: dividing by a number is equal to multiplying the reciprocal of this number.