Associative Property of
Addition
The property that states that when the grouping of addends is
changed, the sum is the same.
Example:
(5 + 8) + 4 = 5 + (8 + 4)
(10 + 84) + 99 = 10 + (84 + 99)
Commutative Property of
Addition
The property that states that when the order of two or more
addends is changed, the sum is the same.
Examples:
4+5=5+4
13 + 48 = 48 + 13
Composite Number
A number having more than two factors.
Divisible
A number is divisible by another number if the quotient is a
counting number and the remainder is zero.
Factor Tree
A diagram that shows the prime factors of a number.
Greatest Common Factor
(GCF)
The greatest factor that two or more numbers have in common
Example:
18: 1, 2, 3, 6, 9, 18
30: 1, 2, 3, 5, 6, 10, 15, 30
6 is the GCF of 18 and 30.
Ladder Diagram
A diagram that shows the steps of repeatedly dividing by a prime number until the quotient is 1. (Also
known as the “Upside-down cake” method.)
Prime Factorization
A number written as the product of all its prime factors.
Prime Number
A number that has exactly two factors, 1 and itself.
Simplest Form
A fraction is in simplest form when the numerator and
denominator have only 1 as their common factor.
Least Common Multiple
(LCM)
The smallest number, other than zero, that is a common multiple of
two or more numbers
Example:
multiples of 6: 6, 12, 18, 24, 30, 36
multiples of 9: 9, 18, 27, 36, 45, 54
The LCM of 6 and 9 is 18.
Least Common
Denominator (LCD)
The least common multiple of two or more denominators
Example: