Third Grade Everyday Math Vocabulary

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Please note that the words for each unit are listed by the order in which they are covered, not alphabetically.
 

Unit One: Routines, Review, & Assessment

unit –a symbol that tells what a number means like feet,

        degrees, minutes, etc.

number grid –a table that lists numbers in order

data base- a collection or set of information

template- a stencil used for drawing geometric shapes

frames and arrows- a diagram used to show a number pattern or

 sequence

tally chart –a chart that uses tally marks to show how many times

 each value appears in a set of data

bar graph –a graph that uses bars to represent numbers in the

          data

name collection box –a place to write equivalent names for the same number

estimation –an answer that is close to the exact answer

calculate –to figure out an answer using numbers  

Unit Two: Adding and Subtracting Whole Numbers

fact family/ number family- related addition and subtraction

        facts or related multiplication and division facts  

difference- the answer to a subtraction problem  

fact extension- a method of using a math fact to solve a bigger

        problem like if 5+7=12 then 50+70=120  

function machine –an imaginary machine used to change numbers

        from input to output according to a given rule  

parts-and-total diagram –a diagram that is used to keep track of

 the numbers and missing information in problems where

two parts are combined to find a total  

number model –equation showing how a number story is solved  

change diagram –a diagram used to keep track of numbers and

        missing information in a number story in which an amount

        is increased or decreased  

ballpark estimate –a good rough estimate used when you don’t

        need an exact answer or to check if an answer makes

        sense  

addend –a number that is added in an addition problem  

sum- the answer to an addition problem  

Unit Three: Linear Measures and Area

inch- unit of measure representing 1/12 of a foot  

line segment- a strait path between two endpoints 

centimeter- a unit of measure representing 1/100 of a

        meter  

millimeter –a unit of measure representing 1/1000 of a

        meter  

perimeter –the distance around a shape  

polygon –a closed figure on a flat surface that is made up of

        line segments joined end-to-end; the line segments of a

        polygon may not cross  

area –the amount of surface inside a shape measured in square

        units  

square foot –a unit of surface area measuring 1 ft X 1 ft  

circumference –the distance around a circle (its perimeter)  

diameter –a line segment that goes through the center of a circle

        and has endpoints on the circle  

Unit Four: Multiplication & Division

multiplication –the operation of putting together numbers of

        equal groups 

array- an arrangement of objects in rows and columns 

factor- any of the numbers that are multiplied to find a product;

        a number that divides another number evenly;

        8 is a factor of 24 

product- the answer to a multiplication problem 

quotient- the answer to a division problem 

dividend- the number to be divided in a division problem 

divisor- the number being divided into the dividend in a division

        problem 

remainder- the amount left over when things are divided or

 shared equally 

square numbers- numbers that result from multiplying 2 of the

        same factors: 2,4,9,16,25,36…

Unit Five: Place Value in Whole Numbers & Decimals

 place value- the system for writing numbers in which the

value of a digit depends on its place in the number 

greater than- > bigger than, the arrow opens to “eat”

          the bigger number 

less than- , smaller than, the arrow points at the smaller

          number 

pie graph- a circular graph that represents amounts as

          different size pieces of “pie” 

decimals- parts of a whole represented in tenths,

hundredths, thousandths, etc.. 

tenths- a decimal representing a part of a whole where

          ten parts would equal one whole 

hundredths- a decimal representing a part of a whole

          where 100 parts would equal one whole 

thousandths- a decimal representing a part of a whole

          where 1000 parts would equal one whole 

decimeter- a unit equal to 10 centimeters or 1/10 of a

          meter

Unit Six: Geometry

line segment –a straight path between two endpoints  

end point –the point at the end of a ray or line segment  

ray- a straight path that has one end point and goes on

        forever  

line- a straight path that goes on forever in both directions  

parallel- always the same distance apart and never meeting or

        crossing each other, no matter how far extended  

intersect –to meet or cross  

angle- a figure that is formed by two rays or two line segments

         that have the same end point  

right angle- a 90o angle, its sides form a square corner  

vertex- the point where the rays of an angle or the sides of

        a polygon or the sides of a polyhedron meet  

equilateral –having sides of equal length  

quadrangle –a polygon that has 4 sides and 4 angles, the same

        as a quadrilateral  

square- a rectangle whose sides are all the same length  

rhombus- a parallelogram with all 4 sides the same length

parallelogram- a four-sided polygon that has 2 pairs of

        parallel sides; the parallel sides are also the same length  

rectangle –a parallelogram whose corners are all right angles  

trapezoid- a four-sided polygon with exactly one pair of parallel

        sides  

adjacent sides- sides that share a vertex  

kite- a four-sided polygon with 2 pairs of equal sides; the equal

 sides are next to each other; the four sides cannot all have

the same length  

degree- a unit of measure for angles; also a unit of measure

        for temperature  

symmetry- figure with at least one line that can divide the

        figure into 2 parts look exactly alike but are pointing in

different directions; if you fold the figure in half the two

halves match exactly  

congruent figures- figures that have the same shape and size  

polyhedron- a geometric solid whose surfaces or faces are all

        formed by polygons  

cone- a solid that has a circular base and a curved surface that

        ends at a point called the apex  

cylinder- a solid that as 2 circular bases that are parallel and the

        same size; the bases are connected by a curved surface  

sphere- a solid with a curved surface that looks like a ball  

pyramid- a solid that has one base that is a polygon; all the

        other sides (or faces) are triangles that come together

        at a point called a vertex or apex  

prism- a solid that has a parallel bases that are polygons with the

 same size and shape; all other faces are parallelograms  

base- a name used for the side of a polygon and a face of a

three-dimensional figure  

face- a flat surface on the outside of a solid  

edge- a line segment or curve where the edges of a solid meet  

 

Unit Seven: Multiplication and Division

factor –any of the numbers that are multiplied to find

          a  product 

product- the answer to a multiplication problem 

square product- the number resulting from multiplying

          a number times that number again

          4, 9, 16, 25, 36…. 

parentheses- the way to tell which part of a multi-step  algorithm should

     be completed first

Unit Eight: Fractions

whole- one complete number or figure, represented

          by the number 1

 denominator- the number below the line in a fraction,

          representing the number of parts you must have to

          make one whole 

numerator- the number above the line in a fraction

          representing the number of parts you have 

equivalent fractions- two or more fractions broken into

          different size pieces (having different denominators) that

         represent equal portions of a whole 

mixed number- a number that combines a whole number and a fraction like

 1 ½

Unit Nine: Multiplication and Division

algorithm- a method of solving a problem

lattice multiplication- a method for solving a multiplication problem using a lattice diagram;

positive number- a number greater than zero

negative number- a number less than zero

degrees Fahrenheit- unit of temperature measurement used in the

    U.S. customary system

degrees Celsius- unit of temperature measurement used in the metric

    system

Unit Ten: Measurement and Data

volume- the amount of space inside a 3-d object, usually measured

    in cubic units

cubic centimeter- unit of volume measurement; a cube measuring

    1 cm X 1 cm X 1 cm

weight- measurement of how heavy something is

capacity- the amount a container or scale can hold

precision- the accuracy to which something can measure

mean- an average number in a set of data; the mean is found by adding all

    of the data values and then dividing by the number of numbers in the

    set of data

median- the middle umber in a set of data when the numbers are put in

    order from smallest to largest or largest to smallest

mode- the number or value that occurs most often in a set of data

coordinate- the location of a point on a grid, usually given in ordered pairs

Unit Eleven: Probability

probability- a number between 0 and 1 that is used to tell the chance 

    of something happening

event- something that happens; tossing heads with a coin and rolling 3 

    with a die are events

random draw- picking out something blindly without looking or in any way

    intentionally making a choice

chance- the possibility that something will occur

certain- absolutely sure to occur

impossible- absolutely sure NOT to occur

percent- an amount out of 100; 100% means all; 50% means half

equally likely- having the same chance of happening
 
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