Explain why $3 \times 5 \times 7 + 7$ is a composite number.

 Given: $3\ \times\ 5\ \times\ 7\ +\ 7$ 

To do: Here we have to explain why the given number is composite.

Solution:

A composite number is a number that is divisible by another number other than by itself and one. The number 2 is the only even prime number. All other even numbers are composite numbers.

Now,

Given number is $3\ \times\ 5\ \times\ 7\ +\ 7$.

Applying BODMAS rule:

$=\ 15\ \times\ 7\ +\ 7$

$=\ 105\ +\ 7$

$=\ \mathbf{112}$

112 is an even number. Also, 112 is divisible by other numbers such as 2, 4, 7, 8, 14, 16, 28 and 56 apart from itself (112) and 1.

So,  $3 \times 5 \times 7 + 7$  is a composite number.

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Updated on: 10-Oct-2022

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