Factor: A number that multiplies with another to make a product
Product: The answer to a multiplication problem
Quotient: The answer to a division problem
Dividend: The number being divided
Divisor: The number you divide by
Remainder: What is left over after dividing
Multiple: What you get when you multiply a number by 1, 2, 3, ...
Prime number: A number greater than 1 with exactly two factors, 1 and itself
Composite number: A number with more than two factors
Array: Objects arranged in equal rows and columns
Equation: A math sentence with an equals sign
Expression: Numbers and operation signs with no equals sign
Variable: A letter that stands for an unknown number
Numerator: The top number in a fraction; how many parts we have
Denominator: The bottom number in a fraction; how many equal parts in the whole
Equivalent fractions: Fractions that name the same amount
Mixed number: A whole number and a fraction together
Improper fraction: A fraction whose numerator is greater than or equal to its denominator
Unit fraction: A fraction with 1 on top
Simplest form: A fraction that cannot be made smaller; the top and bottom share no factor but 1
Decimal: A number written with a decimal point to show parts of a whole
Decimal point: The dot that separates ones from tenths
Tenths: The first place right of the decimal point
Hundredths: The second place right of the decimal point
Round: Replace a number with a nearby number that is easier to use
Estimate: Find an answer that is close but not exact
Regroup: Trade between place values, such as 10 ones for 1 ten
Place value: The value of a digit based on where it sits in a number
Perimeter: The distance around a shape
Area: The amount of flat space inside a shape, in square units
Volume: The amount of space inside a solid, in cubic units
Capacity: How much a container can hold
Angle: Formed where two rays meet at a point
Right angle: An angle of exactly 90 degrees, like a square corner
Acute angle: An angle less than 90 degrees
Obtuse angle: An angle greater than 90 degrees and less than 180 degrees
Straight angle: An angle of exactly 180 degrees
Parallel lines: Lines that stay the same distance apart and never meet
Perpendicular lines: Lines that meet at a right angle
Intersecting lines: Lines that cross each other
Line segment: Part of a line with two endpoints
Ray: Part of a line with one endpoint that goes on forever in one direction
Point: An exact location with no size
Polygon: A closed flat shape made of straight sides
Quadrilateral: Any polygon with 4 sides
Pentagon: A polygon with 5 sides
Hexagon: A polygon with 6 sides
Octagon: A polygon with 8 sides
Symmetry: When a shape can be folded so both halves match exactly
Line of symmetry: The fold line that makes two matching halves
Congruent: Exactly the same size and shape
Face: A flat surface of a solid shape
Edge: Where two faces of a solid meet
Vertex: A corner point of a shape or solid; plural is vertices
Elapsed time: The amount of time that passes from start to end
Data: Facts or numbers collected to learn something
Bar graph: A graph that uses bars to compare amounts
Line plot: A number line with marks above it to show how often values occur
Pictograph: A graph that uses pictures to show data
Survey: Asking a group of people questions to collect data
Mean: The average: add all values and divide by how many there are
Median: The middle value when the data are in order
Mode: The value that appears most often
Range: The highest value minus the lowest value
Commutative property: You can swap the order of numbers when adding or multiplying
Associative property: You can regroup numbers when adding or multiplying and get the same answer
Distributive property: Multiplying a sum equals multiplying each part and adding
Identity property: Adding 0 or multiplying by 1 leaves a number unchanged
Inverse operations: Operations that undo each other
Ordered pair: Two numbers in parentheses that name a point on a grid
Coordinate plane: A flat grid made by a horizontal and a vertical number line
Digit: One of the symbols 0 to 9
Compatible numbers: Numbers that are easy to compute with in your head
Unit: A fixed amount used to measure, like an inch or a gram
Weight: How heavy something is
Mass: The amount of matter in an object
Fraction: A number that names equal parts of a whole

Free flashcards from Peabody at peabody.kids/flashcards/math-vocab-3-5