# 3 # Introduction Mathematical formula is an expression method that people find some connection between natural things and express it in some way. It represents the equal or unequal relationship between the quantities of different things in nature, accurately reflects the internal and external relations of things, and is the basis for us to reach another thing from one thing, so as to better understand the essence and connotation of things. The following is the relevant information, I hope it will help you.

Tisch

Length unit 1 cm = 10/0mm

1 decimeter = 1 0cm1decimeter =100mm.

1 m = 10 decimeter 1 m = 100 cm 1 m = 1000 mm

1km =1000m1km =10000 decimeter1km =100000 cm1km =100000.

mass unit

1t = 1000kg 1kg = 1000g 1kg = 1kg。

Subtraction: 1, minuend-subtraction = difference 2, subtraction = minuend-difference 3, minuend = difference+subtraction.

Addition: 1, Addendum+Addendum = and 2, Addendum = and-Addendum.

Addition and subtraction within 10 thousand

Appendix+Appendix = sum-1 addend = another 1 addend.

Minus-Minus = Difference Minus-Difference = Minus+Minus = Minus

Three-digit addition and subtraction: the parity pairs are neat, counting from single digits.

extreme

The check calculation of addition is 1, the position of the exchange addend, and the sum is unchanged.

2. Subtracting one addend from the sum equals another addend.

Check calculation of subtraction

1, plus or minus the difference equals the minuend.

Characteristics of quadrilateral

1, four straight edges 2, four corners 3, closed graph

Parallelogram feature

1, the opposite side is equal to 2, and the diagonal is equal to 3, which is easy to deform.

Definition of perimeter: the length of a closed figure in one week.

The circumference of a rectangle = length+width+length+width = (length+width) ×2

Circumference of a square = side length ×4

Side length formula: length of rectangle = perimeter ÷2- width of wide rectangle = perimeter ÷2- length.

Division with remainder: The remainder is always less than the divisor.

Have a remainder:

Dividend = divisor × quotient+remainder quotient = (divisor-remainder) ÷ Divider = (divisor-remainder) ÷ quotient

Uncomplete: dividend = divisor × quotient = dividend ÷ divisor = dividend ÷ quotient.

Tisso

Minutes and seconds: 1 century = 100 1 year = 65438+February 1 day =24 hours 1 hour =60 minutes 1 minute =60 seconds/kloc-.

The big month (3 1 day) includes: 1, 3, 5, 7, 8,10,65438+February.

Abortion (30 days) includes April, June and September, 165438+ 10.

February 28th in a normal year and February 29th in a leap year; There are 365 days in a normal year and 366 days in a leap year, with a leap year every four years.

Multiply 0 by any number to get 0 factor × factor = product ÷ 1 factor = another 1 factor.

Score:

Significance of fraction: divide an object into several parts on average, among which several parts.

Meaning of denominator: divide an object into several parts on average.

The meaning of molecules: some of them

Score comparison size:

The numerator is the same, the smaller the denominator, the greater the score;

The denominator is the same, and the larger the numerator, the greater the score.

Simple calculation of fractions: denominator unchanged, numerator addition and subtraction.