For a TV episode I was putting together, we needed some chewables in a prescription bottle, so an actor could shake some out into his hand and chew on them (like Dr. House does with Vicodin).
I decided to use yellow peanut M&Ms, so I went to the vending machine, put in $0.75, and got a bag of peanut M&Ms. I ate all the non-yellow and put the 4 yellow ones in the prescription bottle.
I put another $0.75 in and got another bag. I ate all the non-yellow, and put the 2 yellow ones in the bottle.
Another $0.75, and I was unable to eat anymore, so I started giving them out to cast members. This one had 3 yellows.
The next bag had 5 yellows, and that was enough to fill the prescription bottle.
So, the small bags of M&Ms vary wildly, but I was only counting yellows. 2, 3, 4, and 5.