1. Integers
   Domain numbers
2. Prime numbers
   Mode

Integers are numbers without fractions, which is why they are known as whole numbers. Pi, for example, is not an integer, because it is 3.14 and not 3 or 4. Most people just call integers numbers, which includes negative numbers.

1. An arithmetic mean is the midpoint of a set of numerical values after they been numerically sorted.
   An arithmetic mean is the "average" of a set of numerical values.
2. An arithimetic mean is any integer that can be divided into without a remainder.
   An arithmetic mean is the value of a range of values.

An arithmetic mean is the "average" of a set of numerical values. We typically learn this as "average" instead of "mean" in elementary school, adding up all the numbers in a set and dividing by the set of numbers to determine the average.

1. Algorithm
   Equation
2. Instructions
   Rational

Although the word "algorithm" can be used to describe the process of solving math equations or any other set of instructions, we often hear it now with regard to advertising on our social media. Have you seen people complain about the "Facebook algorithm" when they see unwanted ads? That's because Facebook is looking at all your interactions and demographics and making decisions about what to show you.

1. Range
   Arcsin
2. Angle
   Apex

The pyramid is a three-dimensional shape. A triangle is its two-dimensional analogue, similar to how a sphere is the three-dimensional version of a circle and a cube is that of a square.

1. Congruent
   Perpendicular
2. Slope
   Associative property

Congruent means exactly the same or identical. In geometry, congruent figures are identical, although you may see some tricky iterations like mirror images, making congruent figures *seem* incongruent.

1. Circular arc
   Perimeter
2. Area
   Circumference

In order to determine circumference, you would use the formula 2πr. That means that if you multiply the radius of the circle by 2 and by the number pi, you'll know how far around it is.

1. Law of Cosines
   Cosecant
2. Law of Sines
   Measure of an Angle

The Law of Sines is a trigonometric term that describes how angles relate to the opposite sides of a triangle. Committing these laws to memory will help you if you're studying precalc or calculus! It is described as follows: a/sin A = b/sin B = c/sin C

1. Vertex
   Chord
2. Scalene Triangle
   Amplitude

Amplitude can be a confusing term, because we often think of "amp" as related to making things louder, or amplify. In fact, amplitude simply describes how far a wave ranges in distance from zero.

1. Vinculum
   Radicand
2. Upsilon
   Transversal

Here's a word you probably never thought you'd need to know! Vinculum is just a line, but it's a very particular sort of line: one that indicates that an operation beneath it needs to be done altogether or that the items below it are a unit.

1. Numbers that are used to describe the denoting quantity
   Numerical words that indicate order, such as first, second, third and fourth
2. Numbers describing the elements in a set
   Elements in either finite or infinite sets

Ordinal numbers go ... you guessed it ... in order! Cardinal numbers are just positive integers, beginning with zero. Of course, math has many words to describe the same idea ... or maybe that's an English problem!

1. Cusp
   Concave
2. Median
   Centroid

Every triangle has three "medians" that are straight lines from the vertex, or meeting point of two lines, to the midpoint of the opposite side. Where all three medians intersect is the centroid.

1. Arccosine
   Annulus
2. Cotangent
   Inverse function

An annulus is just the math term for a ring. If you subtract the area of the open space from the area of the entire circle, you can figure out the area of the ring itself. Seems scary, but t's actually pretty approachable!

1. The total area of the exterior surface of a shape
   The term used to describe the of surfaces and solids in space
2. It is the term for all bounded three-dimensional geometric figures.
   A geometric figure in three dimensions excluding interior points

The word "solid" in geometry is just another way to say three-dimensional, like a cube or rectangular prism. Don't worry, that doesn't mean that two-dimensional shapes are liquids, gases or vapors.

1. Cone
   Triangle
2. Pyramid
   Cylinder

Think about an ice cream cone: unlike other geometric figures, it tapers to an end that you need to get to before the ice cream makes it soggy. We'd have a major mess if we were served ice cream in edible cylinders instead!

1. Infinity
   Never-ending
2. Unbounded
   Pythagorean Theorem

If you really think about it, Buzz Lightyear's "To infinity ... and beyond" is impossible, because infinity is our definition for the most beyond — infinity is as far as it goes.

1. Sinusoid
   Amplitude
2. Harmonic Addition Theorem
   Fourier Series

A sinusoid is defined as a curve similar to the sine function, but shifted either in phase, amplitude, period or some combination of these. We're just glad it's not related to stuffy noses and headaches.

1. Radii
   Range
2. Radian
   Circular arc

A radian is a seriously intense concept. You know what a radius is, right? Imaging lying the length of the radius along the circumference of the circle. The angle those two lines create is called the "radian." 3.4 radians = 180 degrees, which is a half-circle. Is your mind blown yet?

1. Rational exponents
   Cube root
2. Domain
   Square root

The cube root of 8 is 2. How do you get that? Divide 8 by 2: 4. Then divide it by 2 again: 2! Cubes are created when we multiply a number by itself and then by itself again: 2 x 2 x 2 = 8, so 2 cubed = 8, and the cube root is the opposite operation, making the cube root of 8 = 2.

1. Coefficient
   Combinatorics
2. Polynomial
   Axes

A coefficient is defined as the number multiplied by a variable in an algebraic expression. An example of this would be the 2 in the equation 2x + 5 =11. In this equation, x = 3, so 2 x 3 = 6, and 6 + 5 = 11.

1. Collinear
   Absolute value
2. Diameter
   Coplanar

Absolute value describes how far any number is from zero, whether that number is positive or negative. So absolute value is always a positive value, although — surprise! — it can also equal zero.

1. Denominator
   Nominator
2. Ellipse
   Dividend

The denominator is what is being divided. In the equation 56 / 8 = 7, the divisor is 8, which means that you have 56 of something and you're splitting it into groups of 8. You end up with 7 groups of 8 (or 8 groups of 7, if 7 is the divisor).

1. Polynomial
   Hypotenuse
2. Vertical
   Horizontal

A horizontal line runs from left to right without going up or down, so it has zero slope. You probably don't want your life to have zero slope, because nothing would ever change!

1. Inverse
   Irrational number
2. Inequality
   Asymptotes

A real number that can't be made by dividing two integers is known as an irrational number. Have you heard of the number e. That's one. So is pi! On the other hand, 1/3, which is a never-ending decimal, is a rational number because it can be expressed with a fraction.

1. A hexagon is a six-sided 2-dimensional shape.
   A hexagon is a six-sided 3-dimensional shape.
2. A hexagon is a eight-sided 2-dimensional shape.
   A hexagon is a three-sided 2-dimensional shape.

A hexagon is a six-sided polygon. Examples of hexagons are all around us and include honeycomb, stop signs, and even fly eyes! Other polygons are as simple as squares and as complicated as the chiliagon, which has 1,000 sides!

1. An Isosceles triangle is a triangle with two unequal sides.
   An Isosceles triangle is a triangle with one 90-degree angle.
2. An Isosceles triangle is a triangle with three unequal sides.
   An Isosceles triangle is a triangle with two equal sides.

In an isosceles triangle, the angles opposite the equal sides are also equal. Other types of triangles are equilateral, which has three equal sides, and scalene, which has no equal sides at all.

1. Two angles that share both a side and a vertex
   A statement of equality between two ratios
2. The number of square units that covers a shape or figure
   A multiple of two or more numbers

If someone paints your portrait, you might want them to create a proportional piece of art: in other words, not a caricature where your head is much larger than any other body part.

1. Any number which, when multiplied by itself, equals the number
   The set of all rational and irrational numbers
2. A value that does not change
   The set of all numbers that can be written as the ratio of two integers with a non-zero denominator

Just like a cube is a number multiplied by itself two times, a square is a number multiplied by itself one time. So 2 squared is 4, and therefore the inverse, or square root, of 4 = 2. What's the square root of 16? How about 144?

1. Line graph
   Pie charts
2. Scatterplot
   Histogram

A scatterplot takes a set of data and plots each point on a plane without drawing any lines between them. Therefore the viewer can see each element and draw their own conclusions about relationships between the data points.

1. Circumference
   Chord
2. Diameter
   Degree

The diameter measures the distance from one side of a circle to the other. The diameter is double the radius. Fun fact: Pi is equal to a circle's circumference divided by its diameter, although, spoiler, the result will always be 3.14!

1. Line that divides a geometric figure into two congruent portions
   A straight set of points that extends into infinity in both directions
2. The study of sound reasoning
   Order of operations acronym

PEMDAS might be something you learned as a kid. It helps you remember the order of operations and when to do what: Start with parentheses, then exponents, multiplication and division, and finally addition and subtraction.

1. Logic
   Mode
2. Median
   Perpendicular

Logic looks for consistency and validity in its results. If you've seen geometric proofs, they're using mathematical logic to offer evidence and reasoning. It's another way of "showing your work."

1. An angle with a measure less than 45°
   An angle with a measure less than 90°
2. An angle with a measure more than 90°
   An angle with a measure that equals to 90°

An acute angle is less than 90°. All triangles have a total of 180° in their three angles. A triangle may have three 60° angles, making it equilateral, or it may have angles of different sizes.

1. Part of a circle’s curve between two points along its circumference
   The measure, in square units, of the inside of a plane figure
2. An arrangement of objects in equal rows
   A characteristic of an object

An arc is any portion besides the entire curve of the circumference of a circle. A chord is a line inside the circle whose endpoints touch the circle, making the diameter the longest chord in any circle.

1. Bar model
   modal model
2. Line graph
   Formula

A bar model offers a visual representation to show the relationship between quantities. For example, you might see bars of different sizes with numbers in them to help teach algebra. If you saw a large bar that said 16 and a smaller bar that said 3x, you would surmise that x is less than 6. If you saw equal bars that said 18 and 3x, you would surmise that x = 6.

1. Beta
   One
2. Sum
   Range

One may be the loneliest number, but we learn all about "one" early. It's the first number most of us learn, and the first math concept we learn, often before we can even string words together!