GED Math key terms

The arithmetic average of a set of numbers, found by adding all the values and dividing by how many values there are. It is sensitive to very large or very small values.

The middle value in a set of numbers arranged in order. If there is an even count, it is the average of the two middle values. Half the data lies below it.

The value that appears most often in a data set. A set may have one mode, several modes, or none if every value occurs equally often.

A comparison of two quantities by division, often written as a fraction or with a colon. It tells how much of one thing there is for each unit of another.

An equation stating that two ratios are equal. Solving one usually means finding a missing value so both sides stay balanced.

A rate expressed for exactly one unit of the second quantity, such as miles per one hour or dollars per one item. Found by dividing the two quantities.

A way of expressing a number as a part of one hundred. For example, 25 percent means 25 out of every 100, or one quarter of the whole.

A measure of how steep a line is, equal to its rise divided by its run. It describes how much the vertical value changes for each unit of horizontal change.

The point where a graph crosses the vertical axis, occurring when the horizontal value equals zero. In a linear equation it often represents a starting amount.

An equation whose graph is a straight line, typically written with the variable raised only to the first power. It has a constant rate of change.

A letter or symbol used to stand for an unknown or changing number in an expression or equation. Solving an equation usually means finding its value.

A mathematical phrase combining numbers, variables, and operations without an equals sign. It can be simplified or evaluated but not solved.

A mathematical statement that two expressions are equal, shown with an equals sign. Solving it means finding values that make the statement true.

The agreed sequence for evaluating a math expression: parentheses first, then exponents, then multiplication and division left to right, then addition and subtraction left to right.

The amount of flat surface enclosed by a shape, measured in square units. Common formulas include length times width for rectangles and pi times radius squared for circles.

The total distance around the outside edge of a flat shape, found by adding the lengths of all its sides. It is measured in linear units.

The amount of space a three-dimensional object occupies, measured in cubic units. For a rectangular box it equals length times width times height.

The longest side of a right triangle, located opposite the right angle. Its length can be found using the Pythagorean relationship among the three sides.

A rule stating that in a right triangle, the square of the hypotenuse equals the sum of the squares of the other two sides. Used to find a missing side length.

A triangle containing one angle of exactly 90 degrees. The side opposite that right angle is the longest side.

A number between 0 and 1 describing how likely an event is, calculated as favorable outcomes divided by total possible outcomes when all outcomes are equally likely.

A way of writing very large or very small numbers as a decimal between 1 and 10 multiplied by a power of ten. It makes extreme values easier to read and compare.

A small raised number showing how many times a base is multiplied by itself. For example, three squared means three times three.

A relationship in which each input value is paired with exactly one output value. It can be shown as a table, graph, or rule.

A testable, tentative explanation for an observation that can be supported or rejected by experiment. It must be phrased so that evidence could show it false.

The factor in an experiment that the researcher deliberately changes or sets. It is the presumed cause whose effect is being measured.

The factor in an experiment that is measured or observed in response to changes in another factor. It is the presumed effect.

A factor held constant across all trials of an experiment so it cannot influence the outcome. Keeping these fixed makes comparisons fair.

Information gathered directly through the senses or with instruments, such as a measured mass or a described color. It forms the evidence on which scientific claims rest.

A conclusion drawn by reasoning from observations rather than from direct measurement. It is an interpretation that goes beyond what was actually seen or recorded.

The process by which green plants use sunlight, water, and carbon dioxide to make sugar and release oxygen. It converts light energy into chemical energy stored in food.

The process by which living cells break down sugar using oxygen to release usable energy, producing carbon dioxide and water. It complements photosynthesis in the carbon cycle.

A community of living organisms interacting with one another and with their nonliving surroundings, such as soil, water, and climate. Energy and matter cycle through it.

A sequence showing how energy passes from one organism to another as each is eaten by the next. It usually begins with a producer and ends with a top consumer.

An organism that makes its own food from sunlight or chemical energy, usually a plant or alga. Producers form the base of most food chains.

An original document or object created during the period being studied, such as a letter, photograph, or diary. It offers firsthand evidence rather than later commentary.

A work that interprets or analyzes events after they happened, such as a textbook or history article. It relies on primary evidence created by others.

A slant or unfair preference that distorts how information is selected or presented. Recognizing it helps a reader judge whether a source is trustworthy.

A formal change or addition to a constitution or law. In the United States, amendments are proposed and ratified through a defined process.

The fundamental set of principles and rules that establishes a government's structure and limits its powers. It typically defines rights and how laws are made.

A system of government in which power is divided between a central national government and regional governments such as states. Each level has its own defined authority.

The central point a passage conveys about its topic, often stated in a topic sentence or implied across several paragraphs. Everything else should support it.

A fact, example, or reason that explains or strengthens the main idea of a text. Details answer the question of why or how the main point is true.

A reasonable conclusion a reader draws by combining clues in a text with background knowledge, even though the author does not state it directly.

Specific information from a text or source used to support a claim or answer. Strong evidence is relevant, accurate, and directly tied to the point being made.

A statement the writer asserts to be true and then supports with reasons and evidence. An effective argument makes its claim clear early.

An opposing view that a writer acknowledges and responds to in order to strengthen an argument. Addressing it shows the writer has considered other positions.

A brief restatement of a text's main points in the reader's own words, leaving out minor details. It should be accurate and much shorter than the original.

Restating a passage's meaning in different words while keeping the original ideas and roughly similar length. Unlike quoting, it does not copy the exact wording.

Presenting another person's words or ideas as one's own without proper credit. It can be avoided by quoting, paraphrasing, and citing sources correctly.

A reference identifying the source of information or ideas used in a piece of writing. It allows readers to locate the original material.

A single sentence that states the central argument or purpose of an essay and previews how it will be developed. It usually appears near the end of the introduction.

A word or phrase that connects ideas and shows how sentences or paragraphs relate, such as however, therefore, or in addition. It guides the reader through the logic.

The attitude an author expresses toward the subject, revealed through word choice and phrasing. It may be serious, humorous, critical, or sympathetic.