4th Grade Harcourt Math Vocabulary
Terms
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 period
 Each group of three digits separated by commas in a multidigit number
 expression
 A part of a number sentence that combines numbers and operation signs but does not have an equal sign
 millions
 The period after thousands
 variable
 A letter or symbol that stands for a number or numbers
 benchmark
 A known number of things that helps you understand the size or amount of a different number of things
 Commutative Property of Addition
 The property that states that when the order of two addends is changed, the sum is the same
 round
 To replace a number with another number that tells about how many or how much
 Associative Property of Addition
 The property that states that you can group addends in different ways and still get the same sum
 Identity Property of Addition
 The property that states that when you add zero to any number, the sum is that number
 century
 A measure of time equal to 100 years
 equation
 A number sentence which shows that two quantities are equal
 decade
 A measure of time equal to 10 years
 second
 A small unit of time; 60 seconds = 1 minute
 survey
 A method of gathering information to record data
 elapsed time
 The time that passes from the start of an activity to the end of that activity
 frequency
 The number of times an event ocurs
 cumulative frequency
 A running total of items being counted
 line plot
 A graph that shows the frequency of data along a number line
 mean
 The number found by dividing the sum of the set of numbers by the number of addends
 range
 The difference between the greatest number and the least number in a set of data
 median
 The middle number in an ordered set of data
 outlier
 A value separated from the rest of the data
 mode
 The number (s) or item(s)that occur most often in a set of data
 stem  and  leaf plot
 A data display that shows groups of data arranged by place value
 stem
 A tens digit in a stemand leaf plot
 doublebar graph
 A graph used to compare similar kinds of data
 leaf
 A ones digit in a stemleaf plot
 trends
 On a graph, areas where the data increase, decrease, or stay the same over time
 scale
 The numbers placed at fixed distances on a graph to help label the graph
 line graph
 A graph that uses a line to show how data change over a period of time
 interval
 The difference between two numbers on the sale of a graph
 circle graph
 A graph in the shape of a circle that shows data as a whole made up of different parts
 inverse operations
 Opposite operations that undo each other, such as addition and subtraction or multiplication and division
 Zero Property of Multiplication
 The property that states that the product of 0 and any number is 0
 fact family
 A set of related multiplication and division or addition and subtaction equations
 Commutative Property of Multiplication
 The property that states that when the order of two factors is changed, the product is the same
 multiple
 The product of a given whole number and another whole number
 Associative Property of Multiplication
 The property that states that you can group factors in different ways and still get the same product
 Identity Property of Multiplication
 The property that states that the product of any number and 1 is that number
 order of operations
 Rules for performing operations in expressions with more than one operation; do the operations inside parentheses, then multiply and divide from left to right, then add and subtract from left to right
 compatible numbers
 Numbers that are easy to compute mentally
 divisible
 Capable of being divided so that the quotient is a whole number and the remainder is zero
 Distributive Property
 The property that states that multiplying a sum by a number is the same as multiplying each addend b the number and then adding the products
 prime number
 A number that has only two factors: 1 and itself
 multistep problem
 A problem requiring more than one step to solve
 composite number
 A whole number that has more than two factors
 remainder
 The amount left over when a number cannot be divided evenly
 square number
 The product of a number and itself
 square root
 One of two equal factors of a number
 ray
 a part of a line that has one endpoint and continues without end in one direction
 point
 An exact location in space
 plane
 A flat surface that extends without end in all dirterctions
 line
 A straight path of points in a plane that continues without end in both directions with no endpoints
 angle
 A figure formed by two line segments or rays that share the same endpoint
 line segment
 A part of a line that includes two points called endpoints and all the points between them
 vertex
 The point at which two rays of an angle or two or more line segments meet in a plane figure or at which three or more edges meet in a solid figure
 protractor
 A tool for measuring the size of an angle
 obtuse angle
 An angle that has a measure greater than 90 and less than 180
 degree ( )
 A unit for measuring angles or temperatures
 straight angle
 An angle that has a measure of 180
 right angle
 An angle that forms a square corner and has a measure of 90
 intersecting lines
 Lines that cross each other at exactly one point
 acute angle
 An angle that has a measure greater than 0 and less than 90
 parallel lines
 Lines in the same plane that never intersect and are always the same distance apart
 perpendicular lines
 Two lines that intersect to form four right angles
 quadrilateral
 A polygon with four sides
 polygon
 A closed plane figure with straight sides, each of which is a line segment
 pentagon
 A polygon with five sides
 regular polygon
 A polygon whose sides are all the same length
 hexagon
 A polygon with six sides
 triangle
 A polygon with three sides
 octagon
 A polygon with eight sides
 triangular pyramid
 A pyramid that has a triangular base and three triangular faces
 net
 A twodimensional pattern that can be folded to make a threedimensional figue
 edge
 The line segment where two or more faces of a solid figure meet
 volume
 The measure of the amount of space a solid figure occupies
 face
 A polygon that is a flat surface of a solid figure
 cubic unit
 A unit of volume with dimensions of 1 unit * 1 unit * 1 unit
 equivalent decimals
 Two or more decimals that name the same amount
 area
 The number of square units needed to cover a surface
 perimeter
 The distance around a figure
 twodimensional
 Measured in two directions, such as length and width
 formula
 A set of symbols that expresses a mathematical rule
 threedimensional
 Mesured in three directions, such as length, width, and height
 circumference
 The distance around a circle
 triangular prism
 A solid figure that has two triangular bases and three rectangular faces
 milliliter (mL)
 A metric unit for measuring capacity; 1,000 milliliters = 1 liter
 kilogram (kg)
 A metric unit for measuring mass; 1 kilogram = 1,000 grams
 liter (L)
 A metric unit for measuring capacity; 1 liter  1,000 milliliters
 ounce (oz)
 A customary unit for measuring weight; 16 of these are equivalent to 1 pound
 pound (lb)
 A customary unit for measuring weight that is equivalent to 16 ounces
 ton (T)
 A customary unit for measuring weight that is equivalent to 2,000 pounds
 millimeter (mm)
 A metric unit for measuring length or distance; 1,000 millimeters = 1 meter
 centimeter (cm)
 A metric unit for measuring length or distance; 100 centimeters = 1 meter
 decimeter (dm)
 A metric unit for measuring length or distance; 10 decimeters = 1 meters
 meter (m)
 A metric unit for measuring length or distance; 1 meter = 100 centimeters
 kilometer (km)
 A metric unit for measuring length or distance; 1 kilometer = 1,000 meters
 mile (mi)
 A customary unit for measuring length or distance that is equivalent to 5,280 feet
 cup (c)
 A customary unit for measuring capacity that is equivalent to 8 ounces
 capacity
 The amount a container can hold when filled
 pint (pt)
 A customary unit for measuring capacity that is equivalent to 2 cups
 teaspoon (tsp)
 A customary unit for measuring cpacity; 3 of these are equivalent to 1 tablespoon
 quart (qt)
 A customary unit of measuring capacity that is equivalent to 2 pints
 tablespoon (tbsp)
 A customary unit for measuring capacity that is equivalent to 3 teaspoons
 gallon (gal)
 A customary unit for measuring capacity that is equivalent to 4 quarts
 unlikely
 Having a less that even chance of ahppening
 linear units
 Units for measuring length, width, height, or distance
 equally likely
 Having the same chance of happening
 inch (in.)
 A customary unit for measuring length or distance; 12 of these are equivalent to 1 foot
 mathematical probability
 A comparison of the number of favorable outcomes to the number of possible outcomes of an event
 foot (ft)
 A customary unit for measuring length or distance that is equivalent to 12 inches
 tree diagram
 An organized list that shows all possible outcomes of an event
 yard (yd)
 A customary unit for measuring length or distance that is equivalent to 3 feet
 simplest form
 The state a fraction is in when 1 is the only number that can divide evenly into both the numerator and denominator
 outcome
 A possible result of an experiment
 mixed number
 An amount given as a whole number and a fraction
 event
 One outcome or a combination of outcomes in an experiment
 like fractions
 Fractions with the same denominator
 predict
 To make a reasonable guess about what will happen
 unlike fractions
 Fractions with different denominators
 likely
 Having a greater than even chance of happening
 xaxis
 The horizontal line on a coordinate grid, or plane
 yaxis
 Th vertical line on a coordinate grid , or plane
 fraction
 A number that names a part of a whole or part of a group
 numerator
 The number above the bar in a fraction that tells how many parts of the whole or group are being considered
 xcoordinate
 The first number in an ordered pair that tells how far to move horizontally
 denominator
 The number below the bar in a fraction that tells how many equal parts are in the whole or group
 ycoordinate
 The second number in an ordered pair that tells how far to move vertically
 equivalent fractions
 Two or more fractions that name the same amount
 equilateral triangle
 A triangle with three equal, or congruent, sides
 acute triangle
 A triangle with three acute angles
 isosceles triangle
 A triangle with two equal, or congruent, sides
 obtuse triangle
 A triangle with one obtuse angle
 scalene triangle
 A triangle with no equal, or cobgruent, sides
 parallelogram
 A quadrilateral whose opposite sides are parallel and equal, or congruent
 right triangle
 A triangle with one right angle
 rhombus
 A parallelogram with four equal, or congruent, sides
 trapezoid
 A quadrilateral with exactly one pair of parallel sides
 chord
 A line segment that has endpoints on a circle
 Venn diagram
 A diagram that shows relationships among sets of things
 diameter
 A line segment that passes through the center of a circle and has endpoints on the circle
 circle
 A closed figure made up of points that are all the same distance from the center
 radius
 A line segment that has one endpoint at the center of a circle and the other endpoint on the circle
 center
 The point inside a circle that is the same distance from each point on the circle
 compass
 A tool used to construct circles
 line symmetry
 What a figure has if it can be folded about a line so that its two parts match exactly
 transformation
 A movement of a figure to a new position by a translation, reflection, or rotation
 rotational symmetry
 What a figure has if it can be turned about a central point and still look the same in at least two positions
 translation
 A movement of a figure to a new position along a straight line
 congruent
 Having the same size and shape
 reflection
 A movement of a figure to a new position by flipping the figure over a line
 similar
 Having the same shape but possibly different in size
 rotation
 A movement of a figure to a new position by rotating the figure around a point
 tessellation
 A repeating pattern of closed figures that covers a surface with no gaps and no overlaps
 positive numbers
 All numbers to the right of zero on the number line

degree
Fahrenheit ( F)  A standard unit for measuring temperature
 opposites
 Numbers that are the same distance from zero but in opposite directions from zero
 degree Celsius ( C)
 A metric unit for measuring temperature
 inequality
 A mathemmatical sentence that shows that two expressions do not represent the same quantity
 negative numbers
 All numbers to the left of zero on the number line
 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
 gram (g)
 A metric unit for measuring mass; 1.000 grams = 1 kilogram
 thousandth
 One of one thousand equal parts
 mass
 The amount of matter in an object
 decimal point
 A symbol used to separate dollars from cents in money and to separate the ones and the tenths places in a decimal
 decimal
 A number with one or more digits to the right of the decimal point