To use PEMDAS you must first understand it, as with anything. You can either think of it as a word (PEM-das) or an acronym; a common one is “Please Excuse My Dear Aunt Sally”. But each letter does stand for an operation, too.
It’s called “order of operations” for a reason. There’s an order to the operations!
M ultiply D ivide
A dd S ubtract
Notice how the M and the D and the A and the S each share a line? That’s because you must do these operations from left to right. What does this mean? After parenthesis and exponents, you do either multiplication or division, depending on what is on the left. If multiplication is farther left, do that first; if it’s division, then divide first. The same goes for adding and subtracting.
Got it? It’s easy once you get the hang of it! Look at this problem to see PEMDAS in action.
Tips and Warnigs
- Practice makes perfect! Work until you’ve got it down well (it may take a few weeks to fully stick). Like riding a bike, once you have it down, you’ll never forget!
It may be easier for some people to think about “Please Excuse My Dear Aunt Sally” than just the word “PEMDAS”, or maybe vice versa. It depends on the person; use whatever is best for you!
It may take you a few weeks to get the hang of it; don’t get frustrated!