
Third Grade Everyday Math Vocabulary
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
partsandtotal 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 endtoend; 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 90^{o }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 foursided 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 foursided polygon with exactly one pair of parallel
sides
adjacent sides sides that share a vertex
kite a foursided 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
threedimensional 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 multistep 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 3d 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