- The observations gathered from an experiment, survey or observational study. Often the data are a randomly selected sample from an underlying population.
- Statistics or other information represented in a form suitable for processing by computer.
A particular month, day, and year at which some event happened or will happen.
A period of ten years, especially a continuous period, such as 1910~1919 or 2009~2018.
A polygon with ten sides and ten angles.
A solid figure having ten plane faces.
A number written using the base 10.
decimal fraction 十进制分数，小数
A fraction whose denominator is some power of 10, usually indicated by a dot (decimal point or point) written before the numerator: as 0.4 = 4/10; 0.126 = 126/1000.
decimal point 小数点
A dot written in a decimal number, as in 8.6, to indicate the place where values change from positive to negative powers of 10.
To become or cause to become less or smaller, as in number, amount, or intensity.
To take away (a quantity) from another; subtract.
- A unit for measuring angles, equal to 1/360 of a complete revolution.
- A unit of latitude or longitude, equal to 1/360 of a great circle.
- A unit for measuring temperature.
- The highest power or the sum of the powers of any term in a polynomial or by itself: x4 + x + 3 and xyz2 are of the fourth degree.
- The greatest power of the highest order derivative in a differential equation.
The expression written below the line in a common fraction that indicates the number of parts into which one whole is divided. For example, 8 is the denominator of 5/8.
density 浓度; 密度
- The quantity of something per unit measure, especially per unit length, area, or volume.
- The mass per unit volume of a substance under specified conditions of pressure and temperature.
dependent event 相关事件，相依事件
Two events are dependent if the outcome or occurrence of the first affects the outcome or occurrence of the second so that the probability is changed.
descending order 降序
Numbers are arranged from the largest to the smallest number. E.g. 25, 21, 17, 13 and 9 are arranged in descending order.
- Joining two nonadjacent vertices of a polygon.
- Joining two vertices of a polyhedron not in the same face.
- A drawing or plan that outlines and explains the parts, operation, etc.
- A graphic representation of an algebraic or geometric relationship.
A straight line segment passing through the center of a figure, especially of a circle or sphere, and terminating at the periphery.
diamond 菱形; （纸牌的）方块
- An equilateral quadrilateral, especially as placed with its diagonals vertical and horizontal; a lozenge or rhombus.
- One of the four suits (= sets) in a pack/deck of cards. The cards are marked with red diamond shapes.
- The amount by which one quantity is greater or less than another.
- The amount that remains after one quantity is subtracted from another.
difference of two Squares 平方差
Squared (multiplied by itself) number subtracted from another squared number. Every difference of squares may be factored according to the identity. a2 – b2 = (a+b)(a-b)
Any of the numbers from 0 to 9.
digital clock / digital watch 数字时钟
A clock that displays the time in numerical digits rather than by hands on a dial.
The act of expanding or enlarging or the state of being expanded or enlarged.
dimension 尺寸; 维度
- A measure of spatial extent, especially width, height, or length.
- The number of coordinates required to locate a point in space.
directed number 有向数, 有符号数
A number together with a sign.
- The point or region itself.
- A position on a line extending from a specific point toward a point of the compass or toward the nadir or the zenith.
- To sell or offer for sale at a reduced price.
- To reduce in quantity or value.
discrete data 离散数据
Statistics or other information represented in a form suitable for processing by computer.
The distance measured in a particular direction from a reference point. Symbol: s.
The length of the shortest line segment joining two points, or a straight line or curve.
distributive law 分配律
To expand (an expression containing two operators) in such a way that the precedence of the operators is changed; for example, distributing multiplication over addition in a(b + c) yields ab + ac.
To separate into equal parts by the process of mathematical division; apply the mathematical process of division to: Eight divided by four is two.
A quantity to be divided.
Capable of being divided, especially with no remainder: 15 is divisible by 3 and 5.
The operation of determining how many times one quantity is contained in another; the inverse of multiplication.
A polygon with 12 sides and 12 angles.
A polyhedron with 12 faces.
The unit of money in the US, Canada, Australia and several other countries. Symbol: $.
domain of a function 函数的定义域
The set of values of the independent variable for which a function is defined.
Twice as much in size, strength, number, or amount: a double dose.
A group of twelve of the same thing.