## Math Words

An abacus is an ancient device that is used for arithmetic calculations.

An acute angle is less than 90 degrees.

Addition is the adding of numbers to get their sum. 1+1=2, 2+3=5

An angle is the amount of rotation it would take to put one intersecting line on top of another.

Arithmetic is the study of addition, subtraction, multiplication, and division. 1+1=2, 7-4=3

A billion is a thousand million. The Earth is billions of years old. 1,000,000,000.

A budget is a written account of all income and expenses for a person, a family, an organization, or a government. People use budgets to figure out how much money they take in and plan how much they can spend and save.

A chart is a diagram, like a graph or a table, that shows the relationships between things.

All of the points on a circle are the same distance from the center.

A cone is a shape that has a point at one end and a circular opening at the other end. In mathematics, this shape is a half cone.

A couple refers to two people or two objects.

A crescent is the shape of the moon a little before of after the time of the new moon.

A cube is a solid geometric figure with six square faces.

A curve is a wavy line.

A cylinder is a figure with a long round body .

The denominator is the bottom number in a fraction.

The diameter is the longest distance from one side of a circle (or a sphere) to the other.

A diamond is a four-sided figure whose sides are all the same length. People play baseball on a diamond-shaped field.

The dividend is the number that is divided (in long division). The dividend divided by the divisor is the quotient (plus a remainder).

Division is an operation that divides a number into portions.

The divisor is the number that the dividend is divided by (in long division). The dividend divided by the divisor is the quotient (plus a remainder).

A dodecahedron is a twelve-sided geometric solid whose faces are pentagons.

Double means twice or two times.

Dozen is another word for twelve.

Spiders have eight legs. Stop signs have eight sides.

Eighteen (18) is the number between seventeen and nineteen.

Eighty (80) is the number between seventy-nine and eighty-one.

Eleven (11) is ten plus one.

An ellipse is a flattened circle.

When two things are equal they are exactly the same in number, quality, or amount.

The sides of an equilateral triangle are all the same length.

An even number is divisible by two. 0, 2, 4, 6, 8, 10, …

Fahrenheit is a measure of temperature that is abbreviated F. Water freezes at 32°F and boils at 212°F.

The first person or thing comes before the others.

Fifteen (15) is the number after fourteen (14) and before sixteen (16).

Fifty (50) is the number after forty nine (49) and before fifty one (51).

People have five fingers on each hand.

Forty (40) is the number after thirty nine (39) and before forty one (41).

Squares have four sides. Cats and dogs have four legs.

Fourteen (14) is the number after thirteen (13) and before fifteen (15).

Fractals are patterns within patterns within patterns.

A fraction is a part of a whole. Half of an apple is a fraction of an apple. The top number in a fraction is called the numerator; the bottom number in a fraction is called the denominator.

Geometry is the mathematical study of points, lines, angles, and solids.

A graph is a diagram that shows relationships between things.

The mathematical symbol **>** means “greater than.” When one number is greater than a second number, the first one is bigger than the second. For example, 4 is greater than 2, or 4 > 2.

When something is divided into two equal parts, each of these two parts is half of the original object.

The heart is a shape that often symbolizes love.

A heptagon is a seven-sided figure.

A hexaflexagon is a folded geometric figure that can be “flexed” to expose its many sides.

A hexagon is a six-sided figure. Beehives have hexagonal cells.

One hundred (100) is the number after 99 and before 101.

An icosahedron is a twenty-sided geometric solid.

An isosceles triangle has two sides that are the same length and two angles that are the same.

A kite is a four-sided figure in which the two pairs of adjacent sides have the same length.

The mathematical symbol **<** means “less than.” When one number is less than a second number, the first one is smaller than the second. For example, 1 is less than 2, or 1 < 2.

A line segment is a portion of a line.

In long division, the dividend is divided by the divisor, resulting in a quotient plus a remainder.

In a magic square, the rows, columns, and diagonals all add up to the same number.

5 4 6

6 5 4

4 6 5

Mathematics is the study of numbers, shapes, patterns, and logical reasoning.

A million is a thousand thousands. The dinosaurs lived millions of years ago. 1,000,000.

The mathematical symbol **-** means “minus.” Four minus three is written, 4 - 3.

A Möbius strip is a piece of paper with only one side!

Multiplication is a mathematical operation used to compute areas and do other calculations. 1 × 2 = 2, 2 × 3 = 6

The mathematical symbol **×** means “multiply.” Four times three is written, 4 x 3.

Nine is the number between eight and ten. There are nine players on a baseball team.

A nonagon is a nine-sided polygon.

Numbers correspond to points on a number line.

Numbers tell you “how many” or “how much.”

The numerator is the top number in a fraction.

An obtuse angle is greater than ninety degrees.

An octagon is an eight-sided figure. Stop signs are octagons.

An octahedron is an eight-sided geometric solid.

An odd number is not divisible by two. 1, 3, 5, 7, 9, 11, …

One is a small number.

When something is divided into two equal parts, each of these two parts is one half of the original object.

A ball-shaped object is an orb.

An oval is an egg-shaped figure.

Parallel lines extend in the same direction, are always the same distance apart, and never meet.

A parallelogram is a four-sided figure whose opposite sides are parallel.

A pattern is something that is repeated.

A pentagon is a five-sided figure.

Perimeter is the distance around the edges of a figure. For example, the perimeter of a square with side length of a is a+a+a+a=4 times a.

When two lines are perpendicular, they are at right angles (90 degrees).

Pi is the ratio of the circumference of a circle to the diameter of a circle (this ratio is the same for any size circle). Pi is roughly equal to 3.14159.

A pie chart (also called a circle graph) is a diagram that is useful for displaying information about the percentages or parts of a whole.

A point is an exact location, a spot with no width or thickness.

A polygon is a many-sided figure with straight edges.

Polyhedra are solids whose faces are polygons.

A prime number is a positive number that has exactly two factors, 1 and itself. Alternatively, you can think of a prime number as a number greater than one that is not the product of smaller numbers. For example, 13 is a prime number because it can only be divided evenly by 1 and 13. For another example, 14 is not a prime number because it can be divided evenly by 1, 2, 7, and 14. The number one is not a prime number because it has only one factor, 1 itself. 2,3,5,7,11,13,17…

A protractor is a device that measures angles.

A pyramid is a shape that has a flat polygonal base and triangular sides that meet at a point on the top. The pyramids in Egypt are huge buildings build by ancient Egyptians.

A quadrilateral is a four-sided figure. The square, rectangle, rhombus, trapezoid, kite, and parallelogram are quadrilaterals.

The quotient is the answer in long division. The dividend divided by the divisor is the quotient (plus a remainder).

The radius is the distance from the center of a circle (or a sphere) to the edge.

A ratio is the relationship between two numbers, as defined by the result you get when you divide one by the other.

A rectangle is a four-sided figure whose sides are at right angles to each other.

The remainder is the fractional part of the answer in long division. The dividend divided by the divisor is the quotient plus the remainder.

A rhombus is a parallelogram with equal-length sides.

A right angle looks like the corner of a square; it extends ninety degrees.

A right triangle has one angle that is a right angle (extending 90 degrees).

Thousands of years ago, in ancient Rome, the Romans used a system of numbers that we call Roman numerals. In this system, I=1. V=5, X=10, L=50, C=100, D=500, and M=1,000.

The sides of a scalene triangle are all different lengths.

The second person or item comes after the first and before the third.

A semicircle is half a circle.

There are seven days in the week.

Everything has a shape.

Insects have six legs.

A sphere is a ball-shaped object.

A square has four, equally long sides which are at right angles to each other.

A star is a shape that has many points.

Subtraction is the operation of taking one number away from another. 1-1=0, 5-3=2

Tally marks are a quick way of keeping track of numbers in groups of five. One vertical line is made for each of the first four numbers; the fifth number is represented by a diagonal line across the previous four.

People have ten fingers and ten toes.

A tetrahedron is a pyramid formed by four triangles.

The third person or item comes after the first and second.

Thirteen (13) is the number after twelve (12) and before fourteen (14).

Thirty (30) is the number after twenty nine (29) and before thirty one (31).

One thousand (1,000) is a whole number that is equal to 100 times 10.

Three is the number between 2 and 4. A tricycle has three wheels. A triangle has three sides. A Triceratops has three horns. Tri means three!

A torus is a doughnut-shaped object.

A trapezoid is a four-sided figure with exactly two parallel sides.

A triangle is a geometric figure that has three sides.

Twelve (12) is the number between eleven (11) and thirteen (13). Dozen is another word for twelve.

There are twenty (20) apples above.

We have two eyes, two ears, two arms, and two legs.

Two things are unequal if they are not the same. 1 + 1 ≠ 3

A Venn diagram is a diagram that uses overlapping circles to show relationships among sets of things.

Zero (0) is a number that stands for the absence of size or quantity.