This is pretty easy and simple because it was originally for a special needs class, but I've also had success with lower grades as a pre-class warmup.
It should be easy to use. Start the powerpoint and click to make the cups start to shuffle. Click again to reveal where the letter ended up.
If you know how to handle some animations then you can modify this to use different vocab instead of letters. Or you can make it easier/harder by changing the animation speed. The default settings are what I used for an elementary school special needs class.
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