You’re used to writing math expressions with numbers on the outside and operators on the inside: \(3 + 4\), or \(5 * 2 + 7\).
The problem with this way of writing math is that you have to keep track of the order of operations (also called operator precedence). That’s PEMDAS or GEMA or whatever way you learned to remember that: first you do grouping symbols (like parentheses, brackets, fraction bars, and the superscript that tells you something is an exponent), then exponents, then multiplication and division in order left-to-right, then addition and subtraction in order left-to-right.