Math Vocabulary for 7th Grade

86 terms

JamWise Education Team·Updated March 2026

In 7th grade, students in the middle school (6-8) band encounter 86 essential math vocabulary terms. These words form the foundation for classroom discussions, reading comprehension, written assignments, and standardized assessments. Mastering this vocabulary gives students the language they need to express their understanding with clarity and confidence.

Below you will find every math term for 7th grade, organized by topic where applicable. Each term links to a detailed definition page with grade-level explanations, related vocabulary, and connections to JamWise learning resources.

6th Grade (92)8th Grade (107)

expressions

View topic hub

Constant

A value that does not change. In the expression 4x + 7, the number 7 is a constant because it stays the same no matter what x is.

Distributive property

A property that lets you multiply a sum by distributing the multiplier to each addend: a(b + c) = ab + ac. Works with subtraction too.

Equivalent expressions

Expressions that have the same value for every possible value of the variable. You can show they are equivalent by using properties of operations.

Expand

To rewrite an expression by using the distributive property to remove parentheses. Expanding 3(x + 4) gives 3x + 12.

Factor an expression

To rewrite an expression as a product of its factors. Factoring 6x + 12 gives 6(x + 2).

Inequality

A mathematical sentence comparing two expressions using <, >, ≤, or ≥. The solution is often a range of values shown on a number line.

Like terms

Terms that have the same variable raised to the same power. You can combine like terms: 3x + 5x = 8x.

Linear expression

An expression with a variable raised only to the first power. For example, 3x + 7 is linear, but 3x² + 7 is not.

Opposite operations

Operations that undo each other when solving equations. Addition undoes subtraction; multiplication undoes division.

Two-step equation

An equation that takes two operations to solve. For example, 2x + 3 = 11 requires subtracting 3 and then dividing by 2.

Two-step inequality

An inequality that takes two inverse operations to solve. For example, 3x - 5 > 7 requires adding 5, then dividing by 3.

Variable

A letter or symbol that represents an unknown quantity in an expression or equation. The variable can take on different values.

geometry

View topic hub

Adjacent angles

Two angles that share a common side and a common vertex but do not overlap.

Angle

A figure formed by two rays that share a common endpoint called the vertex. Angles are measured in degrees.

Area of a circle

The space enclosed by a circle, calculated using A = πr², where r is the radius.

Area of a triangle

The space inside a triangle, calculated using A = (1/2)bh, where b is the base and h is the height.

Circumference

The distance around a circle. You can find it using C = πd or C = 2πr, where d is the diameter and r is the radius.

Complementary angles

Two angles whose measures add up to 90 degrees. If one angle is 35°, its complement is 55°.

Composite figure

A figure made up of two or more simple geometric shapes. To find its area or volume, break it into parts and add them up.

Congruent

Exactly the same shape and the same size. Congruent figures can be placed on top of each other with a perfect match.

Cross section

The shape you get when you slice through a three-dimensional figure with a flat cut. Slicing a cylinder horizontally gives a circle.

Diameter

A line segment that passes through the center of a circle and touches both sides. The diameter is twice the radius.

Pi

The ratio of any circle's circumference to its diameter. Pi (π) is approximately 3.14159. It is the same for every circle, no matter the size.

Prism

A three-dimensional figure with two identical parallel polygon bases connected by rectangular faces.

Radius

The distance from the center of a circle to any point on the circle. The radius is half the diameter.

Semicircle

Half of a circle, formed by cutting a circle along its diameter. Its area is half the area of the full circle: A = (1/2)πr².

Supplementary angles

Two angles whose measures add up to 180 degrees. If one angle is 120°, its supplement is 60°.

Surface area

The total area of all the outer faces of a three-dimensional figure. You find it by adding up the area of each face.

Triangle inequality

The rule that any side of a triangle must be shorter than the sum of the other two sides. If a + b is not greater than c, the three lengths cannot form a triangle.

Vertical angles

The pair of opposite angles formed when two lines cross. Vertical angles are always equal in measure.

Volume of a prism

The space inside a prism, calculated by multiplying the area of the base times the height: V = Bh.

number-system

View topic hub

Absolute value

The distance a number is from zero on the number line. Absolute value is always positive or zero. Written as |x|.

Additive inverse

Two numbers whose sum is zero. For any number a, its additive inverse is -a. The additive inverse of -7 is 7, because -7 + 7 = 0.

Complex fraction

A fraction where the numerator, denominator, or both contain a fraction. For example, (1/2)/(3/4) is a complex fraction.

Rational number

Any number that can be expressed as a fraction a/b where a and b are integers and b is not zero. This includes positive and negative fractions, integers, and terminating or repeating decimals.

Repeating decimal

A decimal in which one or more digits repeat forever. The fraction 1/3 = 0.333... is a repeating decimal, written as 0.3 with a bar over the 3.

Terminating decimal

A decimal that ends after a finite number of digits. The fraction 1/4 = 0.25 is a terminating decimal.

ratios

View topic hub

Commission

Money earned as a percentage of sales. If a salesperson earns 5% commission on a $2,000 sale, they earn $100.

Constant of proportionality

The constant ratio between two proportional quantities. In y = kx, the value k is the constant of proportionality. It is also the unit rate.

Discount

A reduction in the original price of an item, usually expressed as a percent. A 20% discount on a $50 item saves you $10.

Markup

The amount a seller adds to the cost of an item to set the selling price. If a store buys a shirt for $15 and sells it for $25, the markup is $10.

Percent error

The difference between an estimated value and the actual value, expressed as a percent of the actual value.

Percentage decrease

The amount of decrease expressed as a percent of the original value. If a price goes from $50 to $40, the percentage decrease is 20%.

Percentage increase

The amount of increase expressed as a percent of the original value. If a price goes from $20 to $25, the percentage increase is 25%.

Proportion

An equation that states two ratios are equal. For example, 3/4 = 6/8 is a proportion.

Proportional relationship

A relationship between two quantities where the ratio stays constant. Its graph is a straight line that passes through the origin (0,0).

Ratio

A comparison of two quantities that shows how many times one value contains the other. Can be written as a:b, a/b, or a to b.

Scale

The ratio between measurements on a drawing or model and the actual measurements. A scale of 1:100 means 1 cm on the drawing equals 100 cm in real life.

Scale drawing

A drawing that represents a real object where all measurements are proportional. A map is a scale drawing of a larger area.

Scale factor

The ratio used to enlarge or reduce a figure. A scale factor of 2 means every length is doubled.

Scaled copy

A copy of a figure where every length is multiplied by the same scale factor. The shape stays the same but the size changes.

Simple interest

Money earned or paid on a principal amount, calculated using I = Prt, where P is principal, r is rate, and t is time.

Tape diagram

A visual model using rectangles to show how parts relate to a whole or to each other. Useful for solving ratio and percent problems.

Tax

An additional amount added to the price of goods or services, calculated as a percent of the cost. Sales tax is a common example.

Tip

An extra amount of money given for a service, usually calculated as a percent of the bill. A 15% tip on a $40 meal is $6.

Unit rate

A rate in which the second quantity is one unit. If 150 miles takes 3 hours, the unit rate is 50 miles per hour.

statistics

View topic hub

Biased sample

A sample that does not fairly represent the whole population because of how it was chosen. Asking only athletes about favorite sports is biased.

Chance experiment

An activity you can repeat where you do not know what will happen each time. Rolling a die and flipping a coin are chance experiments.

Compound event

An event made up of two or more simple events happening together. Flipping a coin AND rolling a die is a compound event.

Event

An outcome or set of outcomes from a chance experiment. Rolling an even number on a die is an event that includes outcomes 2, 4, and 6.

Experimental probability

The probability of an event based on actual experiments or observations. It equals the number of times the event happened divided by the total number of trials.

Inference

A conclusion you draw about a population based on data from a sample. If 60% of a sample prefers pizza, you infer about 60% of the whole group does too.

Interquartile range

The IQR is the difference between the third quartile and the first quartile. It measures the spread of the middle 50% of the data.

Mean

The average of a data set, found by adding all values and dividing by the number of values. Also called the arithmetic mean.

Mean absolute deviation

The MAD is the average distance between each data point and the mean. It tells you how spread out the data is from the center.

Median

The middle value of an ordered data set. If there are two middle values, the median is their average.

Outcome

A possible result of a chance experiment. When you roll a die, the outcomes are 1, 2, 3, 4, 5, and 6.

Population

The entire group you want to study or collect data about. If you want to know the favorite lunch of all 6th graders, the population is all 6th graders.

Probability

A number between 0 and 1 that describes how likely an event is to happen. 0 means impossible and 1 means certain.

Random sampling

A method of choosing a sample where every member of the population has an equal chance of being selected.

Representative sample

A sample that accurately reflects the characteristics of the entire population. It should be chosen randomly to avoid bias.

Sample

A smaller group chosen from the population to represent it. A good sample is random and representative of the whole population.

Sample space

The set of all possible outcomes of an experiment. For a coin flip, the sample space is {heads, tails}.

Simulation

A model used to imitate a real-world situation and study probability. You might use a random number generator to simulate rolling a die.

Theoretical probability

The probability of an event based on reasoning about equally likely outcomes. The theoretical probability of rolling a 3 on a fair die is 1/6.