So, let's say I had a list of numbers. The stem is the first digit or digits and the leaf is the last digit.
Here are the scores from the last test:
52, 64, 77, 77, 78, 82, 83, 85, 89, 90, 92, 95, 97
The stem and leaf plot would look like...
5 2
6 4
7 7 7 8
8 2 3 5 9
9 0 2 5 7
Make sense?