To decompose means to break down into smaller parts or simpler substances. When a fallen log decomposes in the forest, bacteria and fungi gradually break it down into soil. When food scraps decompose in a compost bin, they transform into rich, dark material that helps gardens grow. This process might take weeks, months, or even years, depending on what's decomposing.

In math, decompose means something different but related: breaking a number or shape into its parts to understand it better. You might decompose the number 47 into 40 plus 7, or decompose a rectangle into two triangles. This helps you see the structure of what you're working with.

The opposite of decompose is compose, which means to put things together. A composer arranges musical notes into a symphony, while decomposition takes complex things apart. Scientists study how things decompose to understand nature's recycling system, where nothing truly disappears but instead transforms into something new. Every autumn leaf that decomposes eventually becomes part of the soil that feeds next spring's flowers.