FIRST IN MATH  Glossary of Math Terms 
FIRST IN MATH  Glosario de términos matemáticos 
A Acute Angle: An angle with a measure less than 90º Addend: Any number that is being added. Adjacent angles: Two angles that share a common side and vertex, but don’t overlap. Algorithm: A stepbystep solution to a problem. Analog Time: Time displayed on a timepiece having hour and minute hands. Area: The measure, in square units, of the inside of a plane figure. Array: A rectangular arrangement of objects in equal rows or columns. Attribute: A property of an object. (Example: color or shape) B Bar Graph : A graph that uses bars to show data. Benchmark fractions: Commonly used fractions, often for estimation. C Capacity: The amount that something can hold. Chord: A line segment whose endpoints are on a circle. Circumference: The distance around a circle. Combination: A group of items. Placing these items in a different order does not create a new combination. Complementary Angles: Two angles whose measurements add to 90°. Compose (Composition): Put together, join. Composite number: A whole number having more than two factors. Cone: A solid figure that has a circular base and one vertex. Congruent: Having the same size and shape. EXAMPLE  Congruent angles have the same measure; congruent segments have the same length. Cube: (noun) A rectangular solid having six congruent, square faces. Cube: (verb) To raise a quantity or number to the third power. (x)(x)(x) Cylinder: A threedimensional figure with two circular bases, which are parallel and congruent. D Decompose (Decomposition): Take apart, separate. Denominator: The bottom number of a fraction. Diameter: A line segment that has endpoints on a circle and passes through the center of the circle. Difference: The answer in a subtraction problem. EXAMPLE: 8  3 = 5; 5 is the difference. E Edge: The line segment where two faces of a solid figure meet. Equation: A statement that two mathematical expressions are equal. Equilateral triangle: A triangle with all three sides of equal length. The angles of an equilateral triangle are always 60° Endpoint: Either of two points marking the end of a line segment. Equivalent: Having the same value. Estimate: A close guess of the actual amount. Expanded form: Writing out a number to show the value of each digit. (Also called Expanded notation) Expanded notation: A way to write numbers that shows the value of each
digit Exponent: Written as a small number to the right and above the base number. An exponent shows how many times a number is to be multiplied by itself. Expression: A variable, or any combination of numbers, variables, and symbols that represents a mathematical relationship (EXAMPLE: 24 x 2 + 5 or 4a – 9). Exterior Angles: The angle formed by any side of a polygon and the extension of its adjacent side. Even number: Any integer that can be divided evenly by 2. F Face: A plane figure that serves as one side of a solid figure. Fact family: A set of related addition and subtraction, or multiplication and division equations using the same numbers (EXAMPLE: 6+9=15, 159=6, 9+6=15, 156=9). Factor: A whole number that divides evenly into another whole number (EXAMPLE: 1, 3, 5, and 15 are factors of 15). Factor pairs: Any two numbers being multiplied together that give you a chosen number. (Example: Some factor pairs of 16 are: 8x2, 4x4, and 16x1) Function: A relation in which every input value has a unique output value. G Glide reflection: A combination of two transformations: a reflection over a line followed by a translation in the same direction as the line. Greatest common factor (GCF): The largest factor that 2 or more numbers have in common. H Heptagon/Septagon: A polygon with 7 sides. Each interior angle in a regular heptagon/septagon has a measure of 128.57°. Hexagon: A polygon with 6 sides. Each interior angle in a regular hexagon has a measure of 120°.Histogram: A bar graph in which the labels for the bars are numerical intervals. Hypotenuse: The longest side of a right triangle (which is also the side opposite the right angle). I Improper fraction: A fraction where the numerator (the top number) is greater than or equal to the denominator (the bottom number). Inequality: A mathematical sentence that contains a symbol that shows the terms on either side of the symbol are unequal (EXAMPLE: 3+4>6). Integer: Any of the natural numbers, the negatives of these numbers, or zero. A whole number (a number that is not a fraction). Interior Angles: An angle inside a polygon. Intersecting lines: Lines that cross. Interval: The distance between two points or events. Inverse operation: The operation that reverses the effect of another operation. (Example: Addition and subtraction are inverse operations) Irrational Number: a number that cannot be written as a simple fraction  it's decimal goes on forever without repeating. It is called "irrational" because it cannot be written as a ratio (or fraction). Isosceles triangle: A triangle with two equal sides. L Least common denominator (LCD): The least common multiple of the denominators in two or more fractions. Least common multiple (LCM): The smallest number, other than zero, that is a common multiple of two or more numbers. Leg (of a right triangle): Either of the two sides that form the right angle in a right triangle. Line: A straight path extending in both directions with no endpoints. Line of symmetry: A line that divides a figure into two halves that are mirror images of each other. Line plot: A graph showing the frequency of data on a number line. Line segment: A part of a line with two endpoints. M Mass: A measure of how much matter is in an object. (Commonly measured as weight) Maximum: The largest value possible. Mean (average): The number found by dividing the sum of a set of numbers by the number of addends. Median: The middle number in an ordered set of data, or the average of the two middle numbers when the set has two middle numbers. Minimum: The smallest value possible. Mixed number: A whole number and a fraction written as one number. Mode: The number(s) that occurs most often in a set of data. Multiples: The product of a given whole number and another whole number (EXAMPLE: multiples of 4 are 4, 8, 12, 16….). N Nonagon: A polygon with 9 sides. Each interior angle in a regular nonagon has a measure of 140°. Number line: A line with numbers placed in their correct position. Numerator: The top number of a fraction. Number sentence: An equation or inequality with numbers. O Obtuse angle: An angle with a measure more than 90º. Octagon: A polygon with 8 sides. Each interior angle in a regular octagon has a measure of 135°. Odd number: Any integer that CANNOT be divided evenly by 2. Ordered pair: A pair of numbers used to locate a point on a coordinate grid. The first number tells how far to move horizontally, and the second number tells how far to move vertically. P Parallel lines: Lines that never intersect and are always the same distance apart. Parallelogram: A quadrilateral whose opposite sides are parallel and congruent.
Perimeter: The distance around a figure. Permutation: The action of changing the arrangement, especially the linear order, of a set of items. Perpendicular lines: Two lines, segments or rays that intersect to form right angles. Pictograph: A graph that uses pictures to show and compare information. Plane: A flat surface that extends infinitely in all directions. Point: An exact location or position. It has no size, only position. Polygon: A closed plane shape made with three or more straight sides. Prime number: A whole number that has exactly two factors, 1 and itself. Probability: The chance an event will occur. Product: The answer to a multiplication problem. EXAMPLE: 6 x 2 = 12; the product is 12. Properties of Operations: An operation works to change numbers. There are six operations: addition, subtraction, multiplication, division, raising to powers, and taking roots. Protractor: An instrument used in measuring or drawing angles. Pyramid: A solid figure with a polygon base and triangular sides that
meet at a single point (vertex).
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Quadrilateral: A polygon with 4 sides. Quotient: The answer that is a result of dividing one number by another. R Radius: A line segment that has one endpoint on a circle and the other endpoint at the center of the circle. Range: The difference between the greatest and least numbers in a set of data. Rate: A ratio that compares two quantities having different units (EXAMPLE: 95 miles in 2 hours). Ratio: A comparison of two numbers using division. Ray: A part of a line that has one endpoint and continues without end in one direction. Rectangular prism: A solid figure in which all six faces are rectangles.
Reflex Angles: An angle greater than 180°. Regular polygon: A polygon that has all sides congruent and all angles congruent. Remainder: The amount left over when a number cannot be divided equally. Repeating decimal: A decimal that has a repeating sequence of numbers after the decimal point. Rhombus: A parallelogram with four equal sides.
Right triangle: A triangle that has a 90º angle. Rotation (turn): A movement of a figure that turns that figure around a fixed point. Round: Changing a number to its nearest group of ten, hundred, thousand, etc. (e.g. 631 rounded to the nearest ten = 630; 631 rounded to its nearest hundred = 600; 631 rounded to its nearest thousand = 1,000) S Scalene triangle: A triangle in which no sides are equal. Similar polygons: Polygons that have the same shape, but not necessarily the same size. Corresponding sides of similar polygons are proportional. Sphere: A solid figure that has all points the same distance from the center. Square: (noun) A 4sided polygon where all sides have equal length and every angle is a right angle (90°). Square: (verb) To rasie a number or quantity to the second power. (The number is multiplied by itself.) (x)(x) Stem and leaf plot: A way to show a list of numbers in a graph format, where each data value is split into a STEM and a LEAF (usually the digit in the ones place). Example: the numbers 22, 24 and 28 have a stem of "2" and "2", "4", "8" are the leafs. Straight angle: An angle with a measure of 180º. Sum: The answer to an addition problem. EXAMPLE: 12 + 7 = 19; the sum is 19. Supplementary Angles: Two angles whose measurements add to 180°. Symmetry: When a figure can be divided by one straight line resulting in two halves that are mirror images. T Tally chart: A table that uses tally marks to record data. Terminating decimal: A decimal that contains a finite number of digits. Tessellate: To combine plane figures so that they cover an area without any gaps or overlaps. Transformation: The moving of a figure by a translation (slide), rotation (turn) or reflection (flip). Translation (slide): A movement of a figure to a new position without turning or flipping it. Trapezoid: A quadrilateral with exactly one pair of parallel sides. U Unit price: The price of a single item or amount (EXAMPLE: $3.50 per pound). Unit rate: A rate with the second term being one unit (EXAMPLE: 50 mi/gal, 4.5 km/sec). V Variable: A letter or symbol that stands for a number or numbers. Venn diagram: A diagram that shows relationships among sets of objects. Vertex: A point where lines, rays, sides of a polygon or edges of a polyhedron meet (corner). Vertical Angles: Angles opposite each other when two lines cross. Volume (capacity): The amount of space (in cubic units) that a solid figure can hold. W Whole number: Any of the numbers 0, 1, 2, 3, 4, 5, … (and so on). X Xaxis: The horizontal number line on a coordinate plane. Y Yaxis: The vertical number line on a coordinate plane.
