There are a couple of things to remember when applying the PEDMAS/BEDMAS order of operations. Brackets/Parenthesis always come first and exponents come second. When working with multiplication and division, you do whichever comes first as you work from left to right. If multiplication comes first, do it before dividing. The same holds true for addition and subtraction, when the subraction comes first, subtract before you add. It may help to look at BEDMAS like this:B - Brackets or Parenthesis
When you are working with parenthesis and there is more than one set of parenthesis, you will work with the inside set of parenthesis and work your way to the outside parenthesis.
To remember PEDMAS or BEDMAS, the following sentences have been used:
Please Excuse My Dear Aunt Sally.
Big Elephants Destroy Mice and Snails.
Pink Elephants Destroy Mice and Snails
You can make up your own sentence to help you remember the acronym and there certainly are more sentences out there to help you remember the order of operations. If you're creative, make up one that you'll remember.
If you are using a basic calculator to perform the calculations, remember to enter in the calculations as required by BEDMAS or PEDMAS. The more you practice using BEDMAS, the easier it gets.
Once you are comfortable with the understanding of the order of operations, try using a spreadsheet to calculate the order of operations. Spreasheets offer a variety of formulas and computational opportunities when your calculator isn't handy.
Ultimately, it's important to understand the math behind the 'acronym'. Even if the acronym is helpful, understand how, why and when it works is more important.
20 - [3 x (2 + 4)] Do the inside bracket (parenthesis) first.
= 20 - [3 x 6] Do the remaining bracket.
= 20 - 18 Do the subtraction.
(6 - 3)2 - 2 x 4 Do the bracket (parenthesis)
= (3)2 - 2 x 4 Calculate the exponent.
= 9 - 2 x 4 Now multiply
= 9 - 8 Now subtract = 1
= 22 – 3 × (10 – 6) Calculate inside the bracket (parenthesis).
= 22 – 3 × 4 Calculate the exponent.
= 4 - 3 x 4 Do the multiplication.
= 4 - 12 Do the subtraction.