In each of the following numbers, replace * by the smallest digit to make it divisible by $11$.

$810291*3$

Give an example of a number.

Which is divisible by $2$  but not by $4$.

Give an example of a number.

Which is divisible by $3$  but not by $6$.

Give an example of a number.

Which is divisible by $4$ but not by $8$.

Give an example of a number.

Which is divisible by both $2$ and $8$ but not by $16$.

Give an example of a number.

The number which is divisible by both $3$ and $6$ but not by $18$.

Give an example of a number.

Which is divisible by both $4$ and $8$  but not by $32$.

$36$.

Express each of the following as a product of prime numbers.

$42$.