Basically what you do is take around 50 or so Popsicle sticks and write a number from 0 to 9 on each of the sticks. After that, you put the sticks into a plastic cup face down so that the numbers can't be seen.
Then, 2 students step forward and each picks a Popsicle stick.
Now, the game can be played multiple ways:
1. The person with the higher/lower number gets a point
2. You have to take another stick and add or subtract the 2 numbers
3. You could also make each student draw a number of sticks and do a specific task with the numbers drawn..
The point is, this is very versatile and can be played in many different ways, so do as you wish, but the general idea stays the same. Hope you have fun!