Order of Operations
Why 2 + 3 × 4 is 14, not 20.
Concept
One agreed-upon order
Math needs everyone to read an expression the same way, so we fixed an order: Parentheses, Exponents, Multiplication and Division (left to right), Addition and Subtraction (left to right).
Multiplication and division are the same rank — you do whichever comes first reading left to right. Same for addition and subtraction.
P → E → M/D → A/S