This document provides an introduction to basic arithmetic concepts including the four fundamental operations of addition, subtraction, multiplication, and division. It explains key terminology like digits, whole numbers, fractions, and decimal numbers. Examples are provided for how to perform each operation by hand in columns as well as how to check answers. The document also covers converting between whole numbers and fractions, reducing fractions, and changing mixed numbers to improper fractions and vice versa. Practice problems with answers are included throughout to illustrate each concept.