Section $8\mathrm{.}1$: $1,2,7$

Johnny says that $3$ is a multiple of $6$ because you can arrange $3$ cookies into $6$ groups by putting $\frac{1}{2}$ of a cookie in each group. Discuss Johnny's idea in detail: In what way does he have the right idea about what the term multiple means, and in what way does he need to modify his idea?