Hallway Kids

Grades 6 - 8 Math

Glossary of Terms

Area – the amount of space inside a flat figure like a square or triangle, measured in square inches, etc.

Base ten blocks – a set of classroom hands-on materials that represent ones, tens and hundreds as small cubes (ones), rods of 10 small cubes combined (tens), and squares of ten rods combined (hundreds).

Base Ten Blocks

Circumference – the distance around the outside of a circle.

Common Core State Standards

Decimal numbers– Numbers that use a decimal point, such as 3.45 for 3 and 45 hundredths.

Denominator – the bottom number of a fraction.

Fluency – knowing addition and multiplication facts quickly and accurately, usually from memory. (also: fluently)

Function – a mathematical expression that relates two quantities, such as the distance and time that a car travels.

Graduated series – sorting numbers or objects into increasing or decreasing order

Hexagon – six-sided figure

Mean– the average of a set of data

Median – the middle number of a set of data when arranged in numerical order

Negative numbers – numbers that are smaller than zero, such as negative temperatures (e.g. -10 degrees)

Number line – a straight line marked in equal intervals and labeled with consecutive numbers.Number Line Graphic

Numerator – the top number of a fraction

Parallel lines – lines that never cross


Pentagon – five-sided figure

Perimeter– the distance around the outside of a figure. For example, a square where each side is 10 inches has a perimeter of 40 inches.

Perpendicular lines – lines that cross at right angles.


Proof(in geometry) – a formal method of reasoning to support a claim

Proportion or proportional relationship – two quantities that increase or decrease at the same rate.

Pythagorean Theorem– The relationship between the length of the sides of any right triangle. If the sides are labeled a, b and c, where c is the longest side, then the relationship is a2 + b2 = c2.

Quadrilateral– any four-sided figure like a square, rectangle, parallelogram, etc.

Rhombus – a four-sided figure where all sides are the same length (like a square) but the angles are not necessarily right angles.

Right Prism

Rotations, reflections, translations and dilations – ways of moving geometric figures to produce similar figures in different places, orientations or sizes. (also: transformations)

Scatter plot – a way of representing a set of data that has two components, such as the size and cost of cars.

Scientific notation – a method for writing large numbers that uses a power of ten to show how many zeros or places are in the number. For example, 3,000,000 can be written as 3 x 106.

Strategies – Using counting or known math facts to figure out math problems. (also: mental math strategies)

Surface area – the total area of the outside of a three-dimensional object like a box or bottle.

Volume – the amount of space inside a three-dimensional object like a box or bottle.