The real number line is a visual representation of all real numbers arranged in a straight line. Each point on the line corresponds to a unique real number, which can be positive, negative, or zero. The line extends infinitely in both directions, with numbers increasing to the right and decreasing to the left. On the real number line, numbers can be whole numbers, fractions, or irrational numbers like π and √2. This line helps in understanding concepts such as distance, order, and the relationships between different types of numbers, making it a fundamental tool in mathematics.