(A) number and algebraic calculation
1, arithmetic of addition and subtraction:
-additive commutative law: a+b = b+a
-additive associative law: (a+b)+c = a+(b+c)
-Definition of subtraction: a-b = a+(-b)
2. Multiplication and division algorithm:
-multiplicative commutative law: a × b = b × a
-Law of multiplicative association: (a × b) × c = a × (b × c)
-Multiplicative distribution law: a × (b+c) = (a × b)+(a × c)
-definition of division: a ÷ b = c, where a = b× c.
3, the relationship between numbers:
-sequence relation: greater than (>) and less than (
-The relation of the opposite number: a+(-a) = 0.
4, digital algorithm:
Properties of -0: a+0 = a, a × 0 = 0.
The properties of-1:a×1= a.
(2) Formulas for calculating the perimeter and area of graphics.
1, square: perimeter c, area s, side length a.
Perimeter = side length ×4, C=4a
Area = side length × side length, s = a× a.
2. Cube: the volume is V and the side length is A..
Surface area = side length × side length× 6, S=a×a×6.
Volume = side length × side length × side length, v = a× a× a.
3. Rectangular: perimeter c, area s and side length a..
Circumference = (length+width) ×2, C=2(a+b)
Area = length × width, S=ab
4. cuboid: volume v, area s, length a, width b and height h.
Surface area (length× width+length× height+width× height )× 2, S=2(ab+ah+bh)
Volume = length × width × height, V=abh
5. triangle: the area is s, the base length is a, and the height is H.
Area = bottom × height ÷2, S=ah÷2.
Height of triangle = area ×2÷ base of triangle = area ×2÷ height
6. parallelogram: the area is s, the base length is a, and the height is H.
Area = bottom × height, S=ah
7. Trapezoid: the area is S, the upper bottom is A, the lower bottom is B, and the height is H.
Area = (upper bottom+lower bottom) × height ÷2, S=(a+b)× h÷2.
(3) Unit conversion
1, length unit conversion
1 km =1000m.
1 m = 10 decimeter.
1 decimeter = 10/0cm.
1 m = 100 cm。
1 cm = 10/0mm.
2, area unit conversion:
1 m2 = 100 hectare.
1 hectare = 1 10,000 square meters.
1 m2 = 100 square decimeter.
1 square decimeter = 100 square centimeter.
1 cm2 = 100 mm2.
3, the body (volume) product unit conversion:
1 m3 = 1000 cubic decimeter.
1 cubic decimeter = 1000 cubic centimeter.
1 cubic decimeter = 1 liter.
1 cm3 = 1 ml.
1 m3 = 1000 liter.
4, weight unit conversion:
1 ton = 1000 kg.
1 kg =1000g.
1 kg = 1 kg.
5. RMB unit conversion:
1 yuan = 10 angle.
1 angle = 10 point.
1 yuan = 100 integral.
6. Time unit conversion:
1 century = 100 year.
1 year = 65438+ February.
The big month (3 1 day) includes: 1, 3, 5, 7, 8,10,65438+February.
Abortion (30 days) includes: April, June, September,165438+1October.
February 28th in a normal year and February 29th in a leap year.
365 days in normal year; A leap year has 366 days.
1 day =24 hours, 1 hour =60 minutes.
1 minute =60 seconds, 1 hour =3600 seconds.
It is worth noting that the formula can't be memorized, and it needs a lot of practice in the topic to really master it!