Question

The least prime number is?
A. 1
B. 2
C. 3
D. 5

Answer 1

Hint: Prime numbers are those numbers which are divisible by itself or divisible by 1. Here in the problem we have to find out which is the least prime number. That’s why we compare all four numbers with each other and then decide the answer for the least prime number.

Complete step-by-step answer:
First we will start with the given Numbers which are-
$1,2,3,4$
Let's do factors of the given numbers
Factors of the given number $1$
$1 = 1 \times 1$
Factors of the given number $2$
$2 = 2 \times 1$
Factors of the given number $3$
$3 = 3 \times 1$
Factors of the given number $5$
$5 = 5 \times 1$
All numbers are prime except $1$ because the prime number is a positive integer which has exactly two positive divisors, but $1$ has only one positive divisor $1$ itself. So it is not a prime number.
Hence $2,3,4$ are prime numbers.
And the least in them is $2$. So, $2$ is the least prime number.
Hence the answer of the given question is option B.

Note- By using the proper definition of what is prime number, we have factorized all the given options in the answer. After that we see that one is not a prime number because it does not have two divisors. It has only one divisor one itself. That’s why it cannot be a prime number. Rest of the numbers are prime because they have two positive divisors, and least in them is $2$.