WGU D128 Mathematics for Elementary
Educators Exam 2026 – Practice Questions &
Verified Answers (Latest Updated Study
Guide)
WGU D128 Mathematics for Elementary Educators
Practice Exam 2026 – 200 Questions Study Guide
• This study guide contains 200 verified practice questions covering all major topics
tested in WGU D128, complete with correct answers and EXPERT RATIONALEs to
deepen your conceptual understanding.
• Use this material by attempting each question independently before checking the
highlighted correct answer and EXPERT RATIONALE — this active recall approach
maximizes retention and exam readiness.
INSTRUCTIONS: Each question has 5 options (A–E). The correct answer is bolded
and marked with . The EXPERT RATIONALE follows immediately below.
1. Which of the following best describes a prime number?
A) A number divisible by any integer
B) A number with exactly three factors
C) A number divisible only by 1 and itself
D) A number that is always odd
E) A number that is a perfect square
C) A number divisible only by 1 and itself
EXPERT RATIONALE: A prime number has exactly two distinct factors — 1 and itself. For
example, 7 is prime because it can only be divided evenly by 1 and 7.
,2. What is the greatest common factor (GCF) of 36 and 48?
A) 6
B) 8
C) 18
D) 24
E) 12
E) 12
EXPERT RATIONALE: The factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, 36 and the factors of 48
are 1, 2, 3, 4, 6, 8, 12, 16, 24, 48. The greatest common factor is 12.
3. What is the least common multiple (LCM) of 4 and 6?
A) 2
B) 8
C) 18
D) 24
E) 12
E) 12
EXPERT RATIONALE: The multiples of 4 are 4, 8, 12… and multiples of 6 are 6, 12… The
smallest common multiple is 12.
4. Which property is illustrated by 3 × (4 + 5) = 3 × 4 + 3 × 5?
A) Commutative property
B) Associative property
C) Identity property
,D) Distributive property
E) Inverse property
D) Distributive property
EXPERT RATIONALE: The distributive property states that a(b + c) = ab + ac. Multiplying
3 across the sum (4 + 5) demonstrates this property.
5. What is the value of 2³ × 2²?
A) 4
B) 8
C) 16
D) 64
E) 32
E) 32
EXPERT RATIONALE: When multiplying powers with the same base, add exponents: 2³ ×
2² = 2⁵ = 32.
6. Which of the following is an example of the commutative property of
addition?
A) (2 + 3) + 4 = 2 + (3 + 4)
B) 5 + 0 = 5
C) 4 + 5 = 5 + 4
D) 5 + (−5) = 0
E) 3 × (2 + 1) = 6 + 3
C) 4 + 5 = 5 + 4
, EXPERT RATIONALE: The commutative property states that order does not affect the
sum: a + b = b + a.
7. What is 5/8 + 3/8?
A) 8/16
B) 15/64
C) 1
D) 8/8
E) 1/1
C) 1
EXPERT RATIONALE: When denominators are equal, add numerators: 5/8 + 3/8 = 8/8 =
1.
8. Which number is composite?
A) 2
B) 11
C) 13
D) 17
E) 9
E) 9
EXPERT RATIONALE: 9 = 3 × 3, so it has factors other than 1 and itself, making it
composite.
9. What is 3/4 − 1/4?
A) 2/8
Educators Exam 2026 – Practice Questions &
Verified Answers (Latest Updated Study
Guide)
WGU D128 Mathematics for Elementary Educators
Practice Exam 2026 – 200 Questions Study Guide
• This study guide contains 200 verified practice questions covering all major topics
tested in WGU D128, complete with correct answers and EXPERT RATIONALEs to
deepen your conceptual understanding.
• Use this material by attempting each question independently before checking the
highlighted correct answer and EXPERT RATIONALE — this active recall approach
maximizes retention and exam readiness.
INSTRUCTIONS: Each question has 5 options (A–E). The correct answer is bolded
and marked with . The EXPERT RATIONALE follows immediately below.
1. Which of the following best describes a prime number?
A) A number divisible by any integer
B) A number with exactly three factors
C) A number divisible only by 1 and itself
D) A number that is always odd
E) A number that is a perfect square
C) A number divisible only by 1 and itself
EXPERT RATIONALE: A prime number has exactly two distinct factors — 1 and itself. For
example, 7 is prime because it can only be divided evenly by 1 and 7.
,2. What is the greatest common factor (GCF) of 36 and 48?
A) 6
B) 8
C) 18
D) 24
E) 12
E) 12
EXPERT RATIONALE: The factors of 36 are 1, 2, 3, 4, 6, 9, 12, 18, 36 and the factors of 48
are 1, 2, 3, 4, 6, 8, 12, 16, 24, 48. The greatest common factor is 12.
3. What is the least common multiple (LCM) of 4 and 6?
A) 2
B) 8
C) 18
D) 24
E) 12
E) 12
EXPERT RATIONALE: The multiples of 4 are 4, 8, 12… and multiples of 6 are 6, 12… The
smallest common multiple is 12.
4. Which property is illustrated by 3 × (4 + 5) = 3 × 4 + 3 × 5?
A) Commutative property
B) Associative property
C) Identity property
,D) Distributive property
E) Inverse property
D) Distributive property
EXPERT RATIONALE: The distributive property states that a(b + c) = ab + ac. Multiplying
3 across the sum (4 + 5) demonstrates this property.
5. What is the value of 2³ × 2²?
A) 4
B) 8
C) 16
D) 64
E) 32
E) 32
EXPERT RATIONALE: When multiplying powers with the same base, add exponents: 2³ ×
2² = 2⁵ = 32.
6. Which of the following is an example of the commutative property of
addition?
A) (2 + 3) + 4 = 2 + (3 + 4)
B) 5 + 0 = 5
C) 4 + 5 = 5 + 4
D) 5 + (−5) = 0
E) 3 × (2 + 1) = 6 + 3
C) 4 + 5 = 5 + 4
, EXPERT RATIONALE: The commutative property states that order does not affect the
sum: a + b = b + a.
7. What is 5/8 + 3/8?
A) 8/16
B) 15/64
C) 1
D) 8/8
E) 1/1
C) 1
EXPERT RATIONALE: When denominators are equal, add numerators: 5/8 + 3/8 = 8/8 =
1.
8. Which number is composite?
A) 2
B) 11
C) 13
D) 17
E) 9
E) 9
EXPERT RATIONALE: 9 = 3 × 3, so it has factors other than 1 and itself, making it
composite.
9. What is 3/4 − 1/4?
A) 2/8
