Math is easy
There are numbers. They're playing a game of hide and seek. Some of them are hiding. We call them unknowns. Some of them are there to help us find these unknowns. We call them constants or coefficients. Each coefficient together with others and the unknown forms a statement which is true for a specific value of unknowns. We call it an equation. If we have exactly same number of such equations as the number of unknowns, we get a map. This map is called a matrix equation where all coefficients arrange themselves in a 2 dimensional grid. Solving this matrix equation will reveal the values of unknowns.