Fifth Grade Vocabulary

Categorical Data: Data with no established
arrangement or numerical order . Data that can
be put into categories.
Example: For M&Ms, each M&M is either red,
green, blue, yellow, orange or brown. Thus, we
can classify each M&M by putting it in one of
each of these categories.
Compose/Decompose: To put shapes together
(compose) or to take shapes apart (decompose).
The hexagon is composed of six triangles.

The trapezoid
can be decomposed
into a triangle and a rectangle, making it easier
to find its area.
Convex Polygon: A polygon in which all
vertices are “pushed outward.” If you connect
two non-consecutive vertices, the segment
would lie entirely inside the polygon.
Divisibility Rules: Rules that determine whether
a number is divisible by a certain number.
*All even numbers are evenly divisible by two.
*If the sum of the digits of a number is
divisible by 3, the number is divisible by 3.
*Numbers ending in 5 or 0 are divisible by 5.
Edges/Faces: A line segment where two faces of
a polyhedron meet is an edge. A flat surface on a
3-dimensional shape is a face.
Equation (Modeling): A mathematical
sentence that shows that two quantities are equal
To solve an equation, find a value for the
that makes the sentence true.
Exponential Notation: A way to show repeated
multiplication by the same factor. A number
written with a base and an exponent.
Greatest Common Factor/Least Common
The largest number that can be
divided evenly into each number in a set is
called the greatest common factor .

The smallest number that each number in a set
divides into evenly (the smallest multiple of
every number in a set) is called the least
common multiple.

Use a Venn Diagram
to find the LCM and
12 = 2* 2*3
18 = 2*3*3
Their intersection:
2*3 = 6 is the GCF
Their union: 2* 2*3*3 = 36 is the LCM

Inverse Operation: An “operation” that
reverses another operation. It undoes the effect
of another operation such as addition,
subtraction, multiplication or division.
Addition and subtraction are inverse operations
(undo adding 3 by subtracting 3)
Multiplication and division are inverse operations
(undo multiplying by 2 by dividing by 2)
Linear Equations/Inequalities (Solve): An
equation or inequality containing variables of
degree one or constants; (no squares, cubes, etc.)
such as x + 8 = 12. To solve an equation, find a
value for the variable that makes the sentence
x + 8 <12 is a linear inequality
Mean: The average value of a set of data. The
sum of a set of numbers divided by the number
of numbers in the set. It is one of the measures
of central tendency.
In the data set 95, 85, 92, 84, the mean is 89.
Millions/Millionths: The seventh place value
position is the millions. The sixth place value
position after the decimal point is the

One million is written 1,000,000.
One millionth is written

One million pennies

Mixed number: A number that is written using
both a whole number and a fraction.
is a mixed number.
Net: Two-dimensional representation for
constructing 3-dimensional shapes.

A net for a cylinder. The length of the side of
the rectangle is equal to the circumference of
the circle.
Order of Operations : Rules that tell in what
order to perform operations in arithmetic and
: Parentheses, exponents, multiplication
and/or division from left to right, addition and/or
subtraction from left to right.
Parentheses , Exponents, Multiply or Divide
from left to right, Add or Subtract from left to
right. (The mnemonic to remember this is
“Please excuse my dear Aunt Sally”).
Orthogonal/Projective View:
Orthogonal views of an object are from the top,
front and sides.
Projective views are picture views.
Orthogonal views of a rectangular prism:

Projective view:
Outliers: A number which is far removed from
the other numbers in a data set. Technically,
they are values that lie more than one and a half
times the length of the box in a box-andwhiskers
plot from either end of the box.
Upper quartile = 93, lower quartile = 64.

The length of the box or interquartile range
(IQR) is 93 – 64 = 28
So, an outlier is any point that is more than
(1.5)(28) = 42 away from the upper or lower
This means any point greater than 93 + 42=135
or less than 64 − 42 = 22 .
Since there is a data point at 10, (a number less
than 22), it is an outlier.
Polygon (Regular/Irregular): A closed 2-
dimensional figure that is made up of line
segments joined end to end. A regular polygon
is one whose sides are all the same length and
whose angles are all equal.
Regular polygons

Polyhedral (Regular/Platonic) Solids: A
geometric solid with polygons as faces. The
faces intersect at edges and the edges come
together at the vertices.
The five special solids having faces which are
all congruent regular polygons and the same
number of polygons at each vertex are called
Platonic solids.
The five Platonic Solids

Tetrahedron Cube Octahedron
4 faces 6 faces 8 faces

Dodecahedron Icosahedron
12 faces 20 faces
Precision of Measurement: The level of detail
of a measurement, determined by the unit of
measure. Precision depends on the smallest u
of measurement being used. The number of
significant digits in a measurement is an
indication of the precision with which the
measurement was taken.
A ruler with 1/16 "markings would have greater
precision than a ruler with only1/4"
Prism: A solid with two congruent, parallel
faces; its other faces are all parallelograms
formed by joining the vertices of the two bases.
Proper/Improper Fraction: A fraction whose
numerator is less than the denominator is
. A fraction whose numerator is greater
than or equal to its denominator is improper.
Significant Digits: Digits that express a
quantity to a specified degree of accuracy. Non-
zero digits are always significant. Zeros at the
end of a decimal and zeros between two nonzero
digits are significant . Zeros at the end of
whole number and zeros immediately following
a decimal point in front non-zero digits are not

7.957 has 4 significant digits.
0.07957 has 4 significant digits
0.79570 has 5 significant digits.
7,957 has 4 significant digits.
79,570 has 4 significant digits.
79,057 has 5 significant digits.
70,905,007 has 8 significant digits.
Substitution Property : A mathematical rule
what is the value of the expression:
that states that if two quantities are equal one o
the quantities can be substituted for the other in
any expression.
if x=51,what is the value of the expression:
Surface Area: The sums of the areas of the
faces of a solid figure.

The surface area of
this solid
(rectangular prism)
is the sum of the
areas of the six faces:
SA = 2(10) + 2(15) + 2(6) = 62 cubic cm


Terminating/Repeating Decimals: A decimal
number that contains a finite number of digits is
called terminating. A decimal number in which
one or more of its digits repeat infinitely is
called repeating.
0.25 is a terminating decimal
Repeating decimals:
Variable: A letter or other symbol that is used to
represent a number. Numbers are called
constants since their values do not change .
In the equation x + 15 = 60, x is the variable,
15 and 60 are constants.


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