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What sources? WILL ANSWER in comments
Answer:
It stands for Parentheses, Exponents, Multiplication/Division, Addition/Subtraction. PEMDAS is often expanded to the mnemonic "Please Excuse My Dear Aunt Sally" in schools. Canada and New Zealand use BEDMAS, standing for Brackets, Exponents, Division/Multiplication, Addition/Subtraction.
Turn off your computer, wait 10 minutes, turn it back on. Open your browser, and go to the website. If it is still not working, I would assume that this is not a problem with your computer, but the network was not loaded properly, and should be fixed with some patience. In the mean time, you may have the day off.
