A stem and leaf plot is a chart that divides numbers into two columns to represent two different figures. The number on the left represents the first digit. The right side series of numbers represents the amount of data points within that first subset number prefix on the left. In the stem and leaf plot above, it is showing how to use one. The left side is essentially the tens column. Using the key, you can see that it says a 5 in the 2 subset represents a 25. A stem and leaf plot makes a large number of data points easier to show without actually having to write them all out.