Question

Look at the digits 36, 42, 54, 28, 84 and 77Write down all the numbers which have 7 as a factor:

Answer 1

Express the given digits as a prime factorization.

`36=2*2*3*3`

It can be observed that the factor of 36 does not have a factor of 7.

Similarly,

`\begin{gathered} 42=2*3*7 \\ 54=2*3*3*3 \\ 28=2*2*7 \\ 84=2*2*3*7 \\ 77=7*11 \end{gathered}`

Observe that 42, 28, 84, and 77 have a factor of 7.