Unit One Math Vocabulary

Unit One Math Vocabulary
1.2
Number Model
a number sentence that models or fits a number story or situation.
For example, the story Sally had $5.00, and then she earned $8.00. The
number model for this is 5 + 8 = 13.
Number Sentence
A number sentence is a sequence of at least two numbers or expressions
separated by a relationship symbol (=, >, 5 30/5 – 5 = y
Rectangular Arrays
An arrangement of objects in rows and columns.
➢Each row has the same number of parts. (Left to Right)
➢Each column has the same number of parts. (Top to Bottom)
➢It has a rectangular shape.
Example:
••••••
••••••
2 by 6 array

Turn-Around Rule (Commutative Property for Multiplication)
A property of addition and multiplication (not division and subtraction)j
that says that changing the order of the numbers being added or
multiplied doesn’t change the answer.
Examples: 5 + 10 = 15 and 10 + 5 = 15
5 x 6 = 30 and 6 x 5 = 30
1.3
Factor
One of two or more numbers that are multiplied to give a product. The
numbers that are multiplied are called factors of the product.
Example 4 and 3 are factors of 12, because 4 x 3 = 12
Product
The result of multiplying two numbers called factors.
Example In 4 x 3 = 12, the product is 12.
Factor Pair
Two whole-number factors of a number whose product is the number. A
number may have more than one factor pair.
Example The factor pairs for 18 are 1 and 18, 2 and 9, and 3 and 6.

Factor Rainbows
A way to show factor pairs in a list of all the factors of a number. A factor
rainbow can be used to check whether a list of factors is correct.
Example The factors of 24 are: 1 2 3 4 6 8 12 24
1.4
Even Number
A whole number that can be divided by 2 with no remainder is an even
number.
Example Even Numbers are 2, 4, 6, 8, and so on. 0 may be
considered even.
Odd Number
A whole number such as 1, 3, 5, and so on, that cannot be evenly divided
by 2. When an odd number is divided by 2, there is a remainder of 1.
Example
The odd numbers are 1, 2, 5, 7, 9, and so on.
Remainder
An amount left over when one number is divided by another number.
Example If you divide 38 by 5, you get 7 with a remainder of 3.

Divisible by
One whole number is divisible by another whole number if there is no
remainder when you divide.
Example
28 is divisible by 7 because 28 divided by 7 is 4 with a
remainder of 0.
1.5
Quotient
The result of dividing one number by another number.
Example In 35 ÷ 5 = 7 the quotient is 7.
Divisibility Test
A test to find out whether a whole number is divisibly by another whole
number without actually doing the division.
Example A divisibility test for 5 is to check the last digit: if the last digit is
0 or 5, then the number is divisible by 5.
1.6
Composite Number
A whole number that has more than two factors.
Example 4 is a composite number because it has three factors: 1, 2,
and 4.

Prime Number
A whole number that has exactly two factors: itself and 1.
Example 5 is a prime number because its only factors are 5 and 1.
1.7
Square Array
An array that has the same number of rows and columns.
Example
A 4 by 4 array is a square array.
Square Number
A number that is the product of a counting number multiplied by itself.
Example 25 is a square number because 25 = 5 x 5.
The square numbers are 1, 4, 9, 16, 25, and so on.
Exponential Notation
A way to show repeated multiplication by the same factor.
Example 2 3 is exponential notation for 2 x 2 x 2. It tells how many times
the number 2, called the base, is used as a factor.
Exponent Key ^
This is the key that is used on your calculator to show exponents.

Exponent
A small, raised number in exponential notation that tells how many times
the base is to be multiplied by itself.
Example In 5 3 the exponent is 3.
1.8
“Unsquaring” a Number
The same as undoing the result of squaring a number.
Example You can use several methods to unsquare a number. You
can use the random method, the “squeeze” method, or the endings and
products method.
Square Root
The square root of a number n is a number which, when multiplied by
itself, gives the number n.
Example 4 is the square root of 16 because 4 x 4 = 16.
Square-Root Key √
The key on the calculator that finds the square root of a number for you.

1.9
Name-Collection Box
A diagram that is used for writing equivalent names for a number.
Factor String
A number written as a product of at least two whole-number factors.
Example A factor string for the number 24 is 2 x 3 x 4. This factor string
has three factors, so its length is 3. The number 1 is never part of a factor
string.
Length of Factor String
The number of factors a factor string has is its length.
Example Another factor string for 24 is 3 x 8. This factor string has
two factors, so its length is 2.
Prime Factorization
A whole number expressed as a product of prime factors. Every whole
number greater than 1 has a unique prime factorization.
Example The prime factorization of 24 is 2 x 2 x 2 x 3.