A simple equation is a mathematical statement that shows the equality of two expressions. It typically contains variables, which are symbols that represent unknown values, and constants, which are fixed numbers. For example, in the equation x + 3 = 7, x is the variable, and the equation states that when you add 3 to x, the result is 7. To solve a simple equation, you need to isolate the variable on one side of the equation. This often involves performing the same operation on both sides to maintain equality. In the previous example, subtracting 3 from both sides gives x = 4, revealing the value of the variable.