Molecules: molecules
Denominator: Denominator
Addition, subtraction, multiplication and division of fractions: addition, subtraction, multiplication and division of fractions.
Complex Fractions and Pseudo Fractions: Mixed Numbers and Inappropriate Fractions
Complex fraction means that a number consists of an integer and a fraction.
A false score refers to a score whose numerator is greater than the denominator. For example: 7/3
Decimal: Decimal
Scientific notation: scientific notation
Sometimes decimals are expressed as the product of a number with only one digit to the left of the decimal point and the power of 10. This is called scientific notation. For example, 23 1 can be written as 2.31x102, and 0.023 1 x10-2. When a number is expressed in scientific terms, the exponent of 10 indicates the number of digits in the number to be multiplied by the power of 10 to get the product. If the index is positive, the decimal point moves to the right; if the index is negative, the decimal point moves to the left. For example, 20.13x103 equals 20, 130, 1.9 1× 10-4 equals 0.00019/kloc.
Basic Concepts of Mathematics and English Translation 2 1, mode
One or several numbers with the highest frequency in a pile number, such as 1, 1, 1, the modes of 2,3,0,0,5 are 1 and 0.
2. Scope (scope)
The difference between the maximum number and the minimum number in a pile, for example, the range 1, 1, 2,3,5is5-1= 4.
3. Average value
Arithmetic average (arithmetic average), geometric average (geometric average: the n-th root of the product of n numbers)
4. Median (median)
After sorting a pile of numbers, the middle number (odd number) or the average of the middle two numbers (even number), such as "the median of 65438 +0, 7, 4, 9, 2, 2, 2, 5, 8 is 2" and "the median of 65438 +0, 7".
5, standard error (standard deviation)
In a pile of numbers, the sum of the absolute values of the difference between each number and the average value is divided by the number (n) of the pile. For example:
The standard errors of 0, 2, 5, 7 and 6 are:
(|0-4|+|2-4|+|5-4|+|7-4|+|6-4|)/5=2.4
6. Standard deviation
In a pile of numbers, the sum of the squares of the differences between each number and the average value, and then divided by n, for example, the standard deviation of 0, 2, 5, 7 and 6 is 6.8.
7. Standard deviation
Is the square root of the standard deviation, the formula of standard deviation is: d 2 = [(a1-a) 2+(a2-a) 2+...+(an-a) 2]/n, and d is the standard deviation.
8. Triangle Cosine Theorem
C 2 = a 2+b 2-2 AB cost, where t is the included angle between two lines of AB.
9.y = k 1x+b 1, y = k2x+B2, and the condition that two straight lines are perpendicular is K 1K2=- 1.
10. Characteristics of multiples of three
The sum of all numbers is divisible by 3.