Contest 'Skill Testing Questions" and BEDMAS (Brackets,Exponents, Divide, Multiply, Add, Subtract)
Heres a web site that explains it all -- I think I am going to copy and save this information into my 'Contest' folder for reference!
http://math.about.com/library/weekly/aa040502a.htm
'Order of Operations' -- When there is more than one operation involved in a mathematical problem, it must be solved by using the correct order of operations. Remember, calculators will perform operations in the order which you enter them; therefore, you will need to enter the operations in the correct order for the calculator to give you the right answer.
Rules
1. Calculations must be done from left to right.
2. Calculations in brackets (parenthesis) are done first. When you have more than one set of brackets, do the inner brackets first.
3. Exponents (or radicals) must be done next.
4. Multiply and divide in the order the operations occur.
5. Add and subtract in the order the operations occur.
Remember to:
Simplify inside groupings of parentheses, brackets and braces first. Work with the innermost pair, moving outward.
Simplify the exponents.
Do the multiplication and division in order from left to right.
Do the addition and subtraction in order from left to right.
Acronyms to Help you Remember:
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)
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!
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) but bf was right.
