Question

How do you know that 5, 7, 8, 9, 10, and 11 are not factors of 12?

Answer 1

Answer :

Factors of 12 are

$1 \times 12 \\ 2 \times 6 \\ 3 \times 4.$

1. 5 multiplied by any number can never give 12 . Multiples of 5 are
2. $5 \: 10 \: 15 \: 20$
3. 7 multiples are
4. $7 \: 14 \: 21$
5. Same applies for all the listed numbers