Mathematics · Quantitative Aptitude

Number Theory

438 Questions

Number theory explores the properties and relationships of integers, focusing heavily on prime and composite numbers. Key areas include identifying prime numbers, understanding co primes, and exploring mathematical conjectures like Goldbach's. These questions are a core component of quantitative aptitude sections in banking and government exams.

Prime number identificationCo prime propertiesGoldbach conjectureOdd and even numbersDivisibility rules

Number Theory Questions

Multiple choice general knowledge math & puzzles
  1. Mersenne Primes

  2. Leibniz Primes

  3. fermat Primes

  4. Newton Primes

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Mersenne primes are prime numbers of the form $2^n - 1$. Here, $3 (2^2-1)$, $7 (2^3-1)$, $31 (2^5-1)$, and $127 (2^7-1)$ all fit this definition. Fermat primes follow a different formula ($2^{2^n}+1$).

Multiple choice general knowledge math & puzzles
  1. Pseudoperfect Number

  2. Pluperfect Number

  3. Omniperfect Number

  4. None of the above

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A multiperfect number (or k-perfect number) is a number where the sum of all divisors is an integer multiple of the number itself. These are also known as pluperfect numbers. Pseudoperfect numbers refer to a different property (semiperfect).

Multiple choice general knowledge math & puzzles
  1. 899

  2. 599

  3. 299

  4. 799

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

599 is a prime number because it has no divisors other than 1 and itself. Checking divisibility by primes up to sqrt(599) ≈ 24.5 (primes: 2, 3, 5, 7, 11, 13, 17, 19, 23) shows none divide 599 evenly. 899 = 29×31, 299 = 13×23, and 799 = 17×47 are all composite.

Multiple choice general knowledge math & puzzles
  1. 1

  2. 2

  3. 3

  4. 5

Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A prime number is defined as a natural number greater than 1 with exactly two distinct positive divisors: 1 and itself. The number 1 has only one divisor, so it is not prime. Two is the smallest prime number.

Multiple choice general knowledge math & puzzles
  1. 103

  2. 107

  3. 109

  4. None

Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The smallest 3-digit number is 100. Checking numbers upwards: 101 is prime. Since 101 is not listed in the options (103, 107, 109), 'None' is the correct choice. 103, 107, and 109 are primes, but they are larger than 101.

Multiple choice general knowledge
  1. True

  2. False

Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Two is the only even prime number because all other even numbers are divisible by 2, making them composite. A prime number has exactly two factors: 1 and itself. Since any even number greater than 2 has at least three factors (1, 2, and itself), only 2 satisfies the prime number condition among even numbers.