I always say that I love QR codes! Elementary students can use them easily and you can do anything with them. I came across this fraction as decimals QR scavenger hunt that I thought would be really cool. It wouldn't be hard to make one similar if you didn't want to buy it.
http://theelementarymathmaniac.blogspot.com/2014/01/writing-fractions-and-decimals-as.html
