EXERCISE 3.5

If a number is divisible by $3,$ it must be divisible by $9.$

Here, the factor tree for $60$ is given. Write the missing numbers.
 

Here, the factor tree for $60$ is given. Write the sum of missing numbers.

Which factors (other than the number itself) are not included in the prime factorization of a composite number?

Has the prime factorisation been done in the following expression?

$24=2\times 3\times 4$

Has the prime factorisation been done in the following expression?

$56=7\times 2\times 2\times 2$

Has the prime factorisation been done in the following expression?

$70=2\times 5\times 7$

I am the smallest number, having four different prime factors. Can you find me?