Question

choose a counterexample to show the conjecture is false . the conjecture is : any number that is divisible by 4 is also divided by 8

Answer 1

find a multiple of 4, that is eg 1.5 of 8.
like 4 x 3 = 12, but its only 1.5 x 8.
basically any odd multiple of 4, wont be equal to the even requirement of 8.

Answer 2

4 can be divided by 4 but not by 8
so can 12