Re: i saved a game to my sd card ,then deleted it from my tablet,but it disappeared from my sd card
You saved thew game data to the SD card, or you moved the game itself to the card?
If the latter, it's not installing the entire game to the SD card. Android installs apps (games are apps) to internal storage. Pieces of them can be moved to external storage (the SD card), but links are left in internal storage showing where each piece is (one link per piece). As far as Android is concerned, the game is still in internal storage. (As far as the storage interface driver is concerned, the link in internal storage sends it to the SD card to retrieve that piece of code, but Android knows nothing about that.) When you delete the game's files from internal storage, the icon you tap to run the game is pointing to where the game was deleted from - there's nothing there now.
Reinstall the game. Move it to the SD card. If it doesn't save much space, that's because of the way the game was written (probably by dropping controls and backgrounds on a game engine, rather than someone actually writing code), and there's nothing you can do about it - that's how much internal space the game takes when "moved" to the SD card.
What "went wrong", aside from the fact that you deleted the game, is that most people don't understand what "Move to SD card" means or does. Google should never have included the function, or the ability to write apps to do it. If you can't manually root the phone and symlink parts of an app to the SD card, you should just get a phone with enough internal storage for your needs.
Carl Sagan put it best. "We live in a society exquisitely dependent on science and technology, in which hardly anyone knows anything about science and technology." He died almost 20 years ago, and it's a LOT more true today than when he said it. There's almost nothing that's not an adaptation of stone-age technology (like sharp edges, heavy pounding things, etc.) that doesn't have a computer in it - and almost no one but geeks understands computers.