I came across this cute little game awhile back at Shari Sloane's website, kidscount1234 . Her website is FULL of great workstation/center games! PDFs are available for both addition & subtraction on the website.
To make the shakers, all you need is a small water bottle, a couple dice, & a little glitter. After you add the dice & glitter (just a bit-- too much makes it hard for the kids to see the dice), seal it all up with E6000. I've used mine for a couple years, & we've never had a problem.
Hop on over & check out all the other fabulous math ideas!