Download Everyday Math Grade 5 Unit 1 Vocabulary

Grade 5, Ch. 1 Math Vocabulary
• rectangular array
• number model
• fact family
• factors
• product
• factor pair
• divisible by
• divisibility rules
• prime number
• composite number
• square array
• square number
• exponent
• exponential notation
• unsquaring a number
• square root
• factor rainbow
• factor string
• length of factor string
• prime factorization
• factor tree
rectangular array
An arrangement of objects into
rows and columns. Each row has
the same number of objects, and
each column has the same number
of objects.
Example:
This is an array of 8 dots.
4 x 2=8
number model
A number sentence that can be
used to describe a rectangular
array. The first factor is the
number of rows in the array and
the second factor is the number
of columns.
Example:
This is the number model for this
array.
3 x 2=6
fact family
There are four related facts in
every fact family, each using the
same three numbers. In a
multiplication and division fact
family there are two multiplication
facts and two division facts.
Example:
This is the fact family for the
numbers: 3, 9, and 27.
3 x 9 = 27
9 x 3 = 27
27 / 3 = 9
27 / 9 = 3
factors
The numbers being multiplied
together in any multiplication problem.
Example:
The factors for the number model
5 x 2 = 10 are the numbers 5 and 2.
product
The answer in any multiplication
problem.
Example:
The product for the number model
5 x 2 = 10 is the number 10.
factor pair
The two numbers being multiplied
together in a multiplication problem
that will always create the same
product. There can be more than one
factor pair for a number.
Example:
There are 3 factor pairs for the
number 12. They are:
1 and 12
2 and 6
3 and 4
divisible by
When a whole number is divided by
second whole number and the answer
is a whole number, then the first
number is divisible by the second
number.
Examples:
The number 135 is divisible by 5
because the answer is 27.
The number 122 is not divisible by 5
because the answer is 24.4, which is
not a whole number.
divisibility rules
 All numbers are divisible by 1.
 All even numbers (ending in 0, 2, 4,
6, or 8) are divisible by 2.
A number is divisible by 3 if the sum
of its digits is divisible by 3.
A number is divisible by 5 if it ends in
5 or 0.
A number is divisible by 6 if it is
divisible by 2 and 3.
A number is divisible by 9 if the sum
of its digits is divisible by 9.
A number is divisible by 10 if it ends
in 0.
prime number
Any number that has exactly two
factors, the number itself and one.
Example:
The numbers 2, 3, 5, 7, and 11 are prime
numbers since they have only 2
factors.
composite number
Any number with more than two
factors.
Example:
The numbers 4, 6, 8, 9, and 10 are
composite numbers since they have
more than two factors.
square array
A special rectangular array that
always has the same number of rows
as columns.
Example:
3x3=9
square number
Any number product that is a result
of any number times itself.
Example:
The numbers 4, 9, and 25 are square
numbers since 2 x 2 = 4, 3 x 3 = 9,
and 5 x 5 = 25.
exponent
It indicates the number of times you
multiply a number by itself.
Example:
The number 3² can also be written as:
3 times 3, 3 squared, or 3 to the
second power.
exponential notation
Any number written with an
exponent.
Example:
The number 3² is written in
exponential notation, but the number
6 is in standard notation.
unsquaring a number
When you find the number that is
multiplied by itself to make the
square number.
Example:
If you unsquare the number 25, the
result is the number 5.
square root
The name for the number that
results from unsquaring a number.
Example:
The number 5 is the square root of
the number 25.
factor rainbow
In a factor rainbow, the product of
each connected factor pair should
be equal to the number itself.
Example:
Factor Rainbow for the number 18 is:
1
2
3
6
9
18
The lines connect each factor pair for
the number 18.
factor string
A name for a number written as a
product of two or more factors. In
a factor string, the number 1 may
not be used as a factor.
Example:
Factor Strings for the number 20 are:
2 x 10
4x5
2x2x5
All of these strings are equal to 2o.
length of factor string
The length is equal to the number of
factors in each string. The longest
factor string for any number is made
up of all prime numbers.
Example:
Factor String Lengths for the number 20
are:
2 x 10
4x5
2x2x5
Length = 2
Length = 2
Length = 3
All of these strings are equal to 2o.
prime factorization
The name for the longest factor
string of any number.
Example:
Prime factorizations for:
12: 2 x 2 x 3
18: 2 x 3 x 3
100: 2 x 2 x 5 x 5
factor tree
This is an easy way to find all of the
prime factors of a number. First write
the number. Then, underneath write
any factor pair of the number. Then,
write the factor pairs for each of
these numbers. Continue until all of
the numbers left are prime numbers.
Example:
Factor Tree for the number 36:
36
9x4
3x3
2x2