• Calculations must be done from left to right.
• Calculations in brackets (parenthesis) are done first. When you have more than one set of brackets, do the inner brackets first.
• Exponents (or radicals) must be done next.
• Multiply and divide in the order the operations occur.
• Add and subtract in the order the operations occur.

How will you remember this order? Try the following Acronyms:

Please Excuse My Dear Aunt Sally (Parenthesis, Exponents, Multiply, Divide, Add, Subtract)

BEDMAS (Brackets, Exponents, Divide, Multiply, Add, Subtract)

Big Elephants Destroy Mice And Snails (Brackets, Exponents, Divide, Multiply, Add, Subtract)

Pink Elephants Destroy Mice And Snails (Parenthesis, Exponents, Divide, Multiply,Add, Subtract)

Examples

12 ÷ 4 + 32 12 ÷ 4 + 93 + 912 Rule 3: Exponent first Rule 4: Multiply or Divide as they appear Rule 5: Add or Subtract as they appear (42 + 5) - 3 21 - 3 18 Rule 2: Everything in the brackets first Rule 5: Add or Subtract as they appear20 ÷ (12 - 2) X 32 - 220 ÷ 10 X 32 - 220 ÷ 10 X 9 - 218 - 216

Rule 2: Everything in the brackets first Rule 3: Exponents Rule 4: Multiply and Divide as they appear Rule 5: Add or Subtract as they appear Does It Make a Difference? What If I Don't Use the Order of Operations?

Mathematicians were very careful when they developed the order of operations. Without the correct order, watch what happens:

15 + 5 X 10 -- Without following the correct order, I know that 15+5=20 multiplied by 10 gives me the answer of 200.

15 + 5 X 10 -- Following the order of operations, I know that 5X10 = 50 plus 15 = 65. This is the correct answer, the above is not!