Prime and Composite Numbers

Identify the odd composite number from the following.

$15, 26, 31, 37$

Identify the odd composite number from the following.

$7, 9, 12, 31$

Identify the even composite number from the following.

$15, 18, 31, 37$

Identify the even composite number from the following.

$12, 21, 19, 29$

Let's find and note down twin prime numbers. (from $1$ to $100$)

Let's make a grid and find out the prime numbers in between $1$ and $200$ by the Sieve of Eratosthenes method.

Find the odd numbers that come immediately one after the other are both prime numbers.

For example: $3,5$.

Do they have a different name?

Except for $2$, all prime numbers are _____.

Note down the prime numbers between $1$ to $100$ derived from Sieve of Eratosthenes method.

The following grid shows the multiples of the number from $1$ to $10$.

The multiples of $3$ are blue cells.

Note down the multiples of $3$.

The following grid shows the multiples of the number from $1$ to $10$.

The multiples of $2$ are red cells.

Note down the multiples of $2$.

Write down those numbers which have exactly two factors.

Is there a number which is not a factor of itself?

Which is the prime number nearest to $35$?

Write the composite numbers between $1$ and $10$.

Write the prime numbers less than $4$.

Write the prime numbers between $4$ and $10$.

Circle the prime numbers.

$12, 22, 15, 23, 17, 25, 21, 19, 20, 35$

Express $12$ as sum of the two odd prime numbers and write the smallest odd prime number as the final answer.

There are four prime numbers written in ascending order. The product of the first three is $385$ and that of the last three is $1001$. The first prime number is: