Crack open an alkaline 9 volt battery like the ones for transistor radios. You are old enough to know what I'm talking about.
You will find 6 aaaa batteries inside. Alkalines only. Duracell type.
They are all over the place.
Thanks for the offer but after realising that I hadn't pulled batteries to bits since I was a kid 'just to see what makes them tick' I realised that I had never actually assaulted a new fangled Alkaline battery, because they were not around then, but only the old zinc-carbon ones. They just have a stack of six block cells in them.
The 9V Alkaline batteries do indeed have six shiny AAAA batteries inside them.
Now I need to modernise and strip down a few other types to see what's in them. If you see me with my eyebrows burnt off you'll know what happened....
I used to use a hearing aid when I attended meetings in Canada, because I was afraid I might miss something important that someone had to say (invariably I didn't miss anything). Anyway, I brought it with me when I came to Vietnam. I managed to find batteries for it at a shop on Hang Dao street. However I found that I was hearing much more here than I wanted to hear, so I put it away. It's easier (and less painful) to say "excuse me, could you repeat that" or "please - speak slowly".