Why are Android devices now not working with a hundred megs I have an android 4.4 kit kat RCA Voyager tablet. I have 100 mg of internal storage on it. I went to download an app from the Play store that was 10 mg and an error popped up saying I had insufficient space on my device. Why is this and is there a workaround that does not involve deleting apps from my device?
If by "mg" you mean "MB," then 100MB free is not enough for anything on an Android device. While it seems like 100MB free should be enough, Android requires well more than that to be able to function, as it needs breathing room for temp files, caches, and more. While that app is only 10MB now, it could easily need well more than that when unpacked and adding data to the system, and in the process it could bring the system to too little storage for it to function at all. So for safety reasons, it wants far more than that available to install anything.

I don't know that device personally. I know it has a microSD slot. If RCA modified Android to allow you to move apps to SD, that may be your necessary workaround to allow you to install an additional app without uninstalling anything else. If it doesn't, then I'm afraid you're out of luck.