We used decahedron double dice to practice part part whole. The student rolled the dice, they counted out unifix cubes for the outside number and then in a different color counted out unifix cubes for the inside number. They counted the total and wrote that number in a box. They drew a line on the second part and wrote the parts that make up that whole.
You could use a regular dice and roll it twice but I like the ten sided dice so the numbers are bigger.
The students thought they were the coolest dice EVER!
I ordered the dice from Kim Suttons website.