A teacher handed out m notebooks which came in packs with c notebooks in each pack. How many packs were there?

Let’s throw some numbers in here just so it becomes clear what we are asked for.

Let’s say the teacher hands out 12 notebooks that came in packs with 4 notebooks in each pack. If you are asked for the number of packs here you would see that it’s 3. That is 3 packs of 4 give 12.

So you divide the number of notebooks handed out (m) by the number of notebooks per pack (c) to get the number of packs.

The number of packs is m/c