The document explains how to decompose numbers and fractions by breaking them down into their constituent parts. It provides examples of decomposing the numerators of fractions in multiple ways, such as breaking down 4 into 1 + 3, 1 + 1 + 1 + 1, or 2 + 2. The document also demonstrates decomposing mixed numbers by breaking down both the whole number and numerator components. Readers are prompted to practice decomposing numbers on their own.