Question

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

Answer 1

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.



As per BODMAS rule:



3 x 5 x 7 + 7 = 105 + 7

= 112.



112 is an even number and is therefore a composite 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.