Lesson #1: In this introductory lesson, Courtney Brown shows how R can be used to calculate simple arithmetic operations, such as addition, subtraction, multiplication, division, logs, and exponents. Also, obtaining help in R is explained.
Courtney Brown's home page is:
http://www.courtneybrown.com
Also, to download R, go to the following url:
http://cran.r-project.org/