Mathematics Order of Operations
When you have a math problem that involves more than one operation—for example, addition and subtraction, or subtraction and multiplication—which do you do first?
In cases like these, we follow the order of operations. The order in which operations should be done is abbreviated as PEMDAS:
- Multiplication and Division (from left to right)
- Addition and Subtraction (from left to right)
For example, in mathematics and most computer languages, multiplication is granted higher precedence than addition, and it has been this way since the introduction of modern algebraic notation. Thus, the expression 2 + 3 × 4 is interpreted to have the value 2 + (3 × 4) = 14, not (2 + 3) × 4 = 20. With the introduction of exponents in the 16th and 17th centuries, they were given precedence over both addition and multiplication and could be placed only as a superscript to the right of their base. Thus 3 + 52 = 28 and 3 × 52 = 75.
- There are no Parentheses.
- There are no Exponents.
- We start with the Multiplication and Division, working from left to right.
3 x 7 = 21, leaving us with 4 - 21 + 6 ÷ 2 =?
- 6 ÷ 2= 3, leaving us with 4 - 21 + 3 =?
- -21 + 3 = -18, leaving us with 4 - 18 = ?
- We then do the Subtraction: 4 - 18 = -14
Final Answer: -14.