This book aims to teach simple mathematics using geological examples to illustrate mathematical ideas. This approach emphasises the relevance of mathematics to geology, helps to motivate the reader, and gives examples of mathematical concepts in a context familiar to the reader. With an increasing use of computers and quantitative methods in all aspects of geology it is vital that geologists should be seen to be as numerate as their colleagues in other physical sciences. The book begins by discussing basic tools such as the use of symbols to represent geological quantities and the use of scientific notation for expressing very large and very small numbers. Simple functional relationships between geological variables are then covered (for example straight lines, polynomials, logarithms) followed by chapters on algebraic manipulation. The mid-part of the book is devoted to trigonometry (including an introduction to vectors), graph plotting (including triangular plots and stereoplots), and statistics. The last two chapters give an introduction to differential and integral calculus.