Question

Write the set of all prime numbers less than 11 in roster form.

Answer 1

Hint: Prime numbers are those which are positive integers and have only two factors 1 and integer itself. By this definition we will get our required solution.
Complete step-by-step answer:
In the roster form all the elements are being separated by comma $(,)$ and enclosed within braces $\{\}$ .
Suppose if we are asked the numbers between 1 to 4 in roster form, we will write them as $\{2,3\}$ .
Here in this question we are asked to write prime numbers in roster form.
Prime numbers less than 11 are $2,3,5,7$ to write them in roster form, we just include those in curly braces.
Set is a collection of well-defined obtains.
Here we asked to write the set of prime numbers less than 11.
As mentioned the curly braces, we have to write the prime numbers less than 11 are $2,3,5,7$
Now, include these number in set A
A $=\{2,3,5,7\}\Rightarrow $ set of all prime numbers less than 11.
Note: 1 is neither prime nor composite
sets are represented in curly brace $\{\}$
In roster form the ellipses $(......)$ means that set is going till infinity.
Example: N$=\{1,2,3,4,5,......\}$. Here we use ellipses to show that the natural number keeps going after 5 upto infinity.