Fundamentals of Number Theory

Number Theory

A collection of factual questions covering basic number theory concepts such as primes, divisibility, and number systems.

mathematics education integers

18 Questions Easy Ages 13+ Sep 13, 2026

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About this Study Set

This study set covers Number Theory through 18 practice questions. A collection of factual questions covering basic number theory concepts such as primes, divisibility, and number systems. Every question includes the correct answer so you can learn as you go — pick any format above to get started.

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Browse all 18 questions from the Fundamentals of Number Theory study set below. Each question shows the correct answer — select a study format above to practice interactively.

1 What is the smallest prime number?

2 Which of the following numbers is a perfect square?

A 10
B 20
C 25
D 30

3 What is the greatest common divisor (GCD) of 8 and 12?

4 Which of these numbers is a composite number?

A 7
B 9
C 11
D 13

5 What is the sum of the first three positive odd integers?

A 6
B 8
C 9
D 12

6 A number is divisible by 5 if its last digit is:

A 0 or 5
B 1 or 5
C Only 5
D Even

7 What is the product of 0 and any integer?

A 1
B 0
C The integer itself
D Undefined

8 Which of the following is a pair of twin primes?

A 2 and 3
B 3 and 5
C 7 and 9
D 8 and 10

9 What is the value of 2 raised to the power of 3?

10 Which of the following is an irrational number?

A 1/2
B 0.333...
C PI
D 4

11 What is the smallest positive integer?

A 0
B 1
C 2
D -1

12 How many factors does the number 7 have?

13 What is the result of 15 modulo 4?

14 Which number is neither prime nor composite?

15 What is the Least Common Multiple (LCM) of 3 and 5?

A 8
B 10
C 15
D 20

16 What type of number is 13?

A Even
B Composite
C Prime
D Square

17 Which of the following is a multiple of 9?

A 19
B 27
C 39
D 49

18 What is the value of the square root of 64?

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