Define It: Math Terms

Question: Perpendicular

Answer: Two lines are perpendicular if they intersect at a right angle.

Question: Half

Answer: Since 4 ÷ 2 = 2, 2 is half of 4. Ace that question? Try our Fun Facts of Measurement and Math Quiz.

Question: Split

Answer: Division is used to split a number into parts. To split 12 into four parts, 12 is divided by 4: 12 ÷ 4 = 3.

Question: Denominator

Answer: In ⅔, 3 is the denominator of the fraction.

Question: Obtuse angle

Answer: An obtuse angle is sometimes identified as a “fat” angle. If you aced this question, test your skills on our All About Math Quiz.

Question: Parallel

Answer: Two lines that will never cross each other are parallel.

Question: Circumference

Answer: Circumference can be found by multiplying the diameter of a circle by π (roughly 3.14).

Question: Addend

Answer: In 6 + 3 = 9, 6 and 3 are the addends.

Question: Volume

Answer: For a cube, volume equals length × width × height.

Question: Pentagon

Answer: The Pentagon is a building in Arlington, Virginia, named for its five sides.

Question: Remainder

Answer: Also called the leftover, a remainder is the amount “left over” after dividing one integer by another to produce an integer.

Question: Angle

Answer: The point at which two lines intersect is called the vertex.

Question: Probability

Answer: The probability of an event occurring can range from zero to one.

Question: Ray

Answer: A ray has a fixed starting point but no endpoint. If you aced this question, try our Numbers and Mathematics Quiz.

Question: Quadrilateral

Answer: That’s the only qualification a polygon needs to be a quadrilateral: four sides.

Question: Times

Answer: In 2 × 3 = 6, × is the times sign.

Question: Octagon

Answer: The area of a regular (equal-sided) octagon equals 2(1 + √2)a². The symbol a represents the length of one side.

Question: Combine

Answer: Combining 3 with 7 results in 10.

Question: Symmetry

Answer: A shape has symmetry if it can be folded so that its two sides match evenly.

Question: Equation

Answer: An equation must include an equal sign.

Question: Decreased

Answer: If a number has decreased, another number has been subtracted from it.

Question: Expression

Answer: An expression uses numerals, operators (such as + or ÷), and other symbols (such as a letter for an unknown value) to represent a quantity. It does not include an equal sign.

Question: Integer

Answer: If an integer is subtracted from itself, the result is zero, and if a larger integer is subtracted from a smaller one, the result is a negative integer.

Question: Congruent

Answer: Two congruent angles have the same measure.

Question: Acute angle

Answer: An acute angle measures less than 90°. Ace this question? Try our Mathematics: Fact or Fiction Quiz.

Question: Straight angle

Answer: A straight angle appears as a straight line.

Question: Average

Answer: Of the measurements 2 meters, 7 meters, and 9 meters, the average length is 6 meters.

Question: Total

Answer: When adding numbers, the total is the same as the sum.

Question: Line segment

Answer: A line segment includes all points of the line between its two endpoints.

Question: Fraction

Answer: A fraction represents the quotient of two numbers—the division of one number (the numerator) by another (the denominator)—such as ½ or ⅔.

Question: Median

Answer: In a set of numbers listed in ascending order, the median is the number in the middle position.

Question: Perimeter

Answer: Perimeter is the sum of all the sides of a plane area.

Question: Together

Answer: The numbers 6 and 3 together make 9.

Question: Equilateral triangle

Answer: When shapes other than a triangle have all equal sides, they are identified by the word regular. All equilateral triangles are isosceles triangles, but not all isosceles triangles are equilateral triangles.

Question: Scalene triangle

Answer: A scalene triangle has three sides of unequal length and three unequal angles.

Question: Hexagon

Answer: The area of a regular (equal-sided) hexagon equals [(3√3)/2] × a². The symbol a represents the length of one side.

Question: Intersecting lines

Answer: Intersecting lines have angles at their point or points of intersection.

Question: Parallelogram

Answer: Squares, rectangles, and rhombuses are all parallelograms.

Question: More

Answer: If Juan has 11 apples and Tanya has 15, Tanya has 4 more apples than Juan has.

Question: Fewer

Answer: If Willis has 8 fewer papers than Janet has and she has 11 papers, Willis has 3 papers.

Question: Quarter

Answer: The quarter of a number divisible by four can be found by dividing the number by four—for example, 16 ÷ 4 = 4.

Question: Polygon

Answer: Polygons have no curves or openings.

Question: Product

Answer: The product of 6 and 3 is 18.

Question: Mean

Answer: The mean of a set of numbers is found by adding up all the numbers and then dividing the sum by how many numbers there are.

Question: Square

Answer: A polygon having sides of 6 units each and four 90° angles is a square.

Question: Numerator

Answer: In ⅔, 2 is the numerator of the fraction.

Question: Mode

Answer: In a set of numbers, the mode is the number that appears the most often.

Question: Prime

Answer: Prime numbers include 2, 3, 5, 7, 11, 13, and others.

Question: Quotient

Answer: In 6 ÷ 2 = 3, 3 is the quotient.

Question: Right angle

Answer: A right angle is 90°.

Question: Separate

Answer: A group of 20 people can be separated into four groups of 5 people each.

Question: Factor

Answer: Since 6 × 3 = 18, 6 and 3 are factors of 18.

Question: Leftover

Answer: Also called the remainder, a leftover is the amount “left over” after dividing one integer by another to produce an integer.

Question: Change

Answer: If the item costs $5.50 and Alex gives the clerk $10.00, Alex will receive $4.50 in change.

Question: Less

Answer: One expression of 4 less than 10 is 10 − 4.

Question: Cube

Answer: 27 is the cube of 3 because 3³ = 3 × 3 × 3 = 27.

Question: Estimate

Answer: An estimate does not provide the exact value of something.

Question: Circle

Answer: A circle is a geometrical curve consisting of all points in a plane that are the same distance (radius) from a given point (the center).

Question: Isosceles triangle

Answer: The area of an isosceles triangle can be found by multiplying the length of the base by the height and then dividing by 2.

Question: Sum

Answer: In the equation 2 + 3 = 5, 5 is the sum.

Question: Coordinate

Answer: A point on a two-dimensional line graph is usually represented as a pair of coordinates (x, y) that correspond to a position on the graph’s x (horizontal) and y (vertical) axes.

Question: Rhombus

Answer: The area of a rhombus can be found by multiplying the lengths of the diagonals and then dividing by 2.

Question: Increased

Answer: If 5 is increased by 2, the result is 7.

Question: Share

Answer: Two polygons that touch along one side share that side.

Question: Area

Answer: The area of a square can be found by multiplying the length of one side by itself.

Question: Difference

Answer: In 6 − 2 = 4, 4 is the difference.

Question: Plus

Answer: In 6 + 2 = 8, + is the plus sign.