# Order of Operations (Pemdas)

When simplifying algebraic expressions, perform operations within parentheses first and then exponents and then multiplication and then division and then addition and lastly subtraction. This can be remembered by the mnemonic:

PEMDAS

Please Excuse My Dear Aunt Sally

This mnemonic isnâ€™t quite precise enough. Multiplication and division are actually tied in order of operation, as is the pair addition and subtraction. When multiplication and division, or addition and subtraction, appear at the same level in an expression, perform the operations from left to right.

For example, 6 Ã· 2 Ã— 4 = (6 Ã· 2) Ã— 4 = 3 Ã— 4 = 12. To emphasize this left-to-right order, we can use parentheses in the mnemonic: PE(MD)(AS).

Example

1. â€“21
2. 32
3. 45
4. 60
5. 78
Solution

 By performing the division within the innermost parentheses By performing the addition within the innermost parentheses 2 â€“ (5 â€“ 27[3]) = By performing the exponentiation 2 â€“ (5 â€“ 81) = By performing the multiplication within the parentheses 2 â€“ (â€“76) = By performing the subtraction within the parentheses 2 + 76 = By multiplying the two negatives 78