All mathematical formulas from the first volume of the sixth grade to the second volume of the sixth grade
The formulas of the first and second volumes of the sixth grade are: additive commutative law: A+B = B+A; Additive associative law: (a+b)+c = a+(b+c); Multiplicative commutative law: ab = ba Multiplicative associative law: (AB) C = A (BC); Multiplication and distribution law: a (b+c) = ab+AC. Rectangular perimeter = (length+width) × 2; Square perimeter = side length × 4; The circumference of a circle = π× diameter = π× radius× 2. Area of rectangle = length × width; Area of a square = side length × side length; Area of parallelogram = base × height; Area of triangle = base × height ÷ 2; Trapezoidal area = (upper bottom+lower bottom) × height ÷ 2; Area of circle = π× radius; Annular area = external circular area-internal circular area; Surface area of cuboid = (length× width+length× height+width× height) × 2; Average speed = total distance/total time; Meet distance = speed and x meet time, meet time = meet distance ÷ speed and; Discount = current price/original price (discount < 1), current price = original price × discount, original price = current price/discount; Example scale = distance on map ÷ actual distance, actual distance = distance on map ÷ scale, distance on map = actual distance × scale; Catch-up distance = speed difference × catch-up time, catch-up time = catch-up distance/speed difference.