NCERT Solutions for Chapter: Playing with Numbers, Exercise 5: EXERCISE 3.5

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?

$70=2\times 5\times 7$

Determine if $25110$ is divisible by $45.$

$18$ is divisible by both $2$ and $3.$ It is also divisible by $2\times 3=6.$ Similarly, a number is divisible by both $4$ and $6.$ Can we say that the number must also be divisible by $4\times 6=24?$ If not, give an example to justify your answer.

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