Order of Operations

A rule of precedence in solving mathematical expressions.

What kind of expressions need this to be solved?

• Remember, to use the order of operations you need a math expression.– And this expression must include at least two

different math symbols.• Parenthesis, exponents and roots, multiplication,

division, addition, and subtraction symbols.

Would this be an example?

• 2.424+3.563• NO!• Why?–It only contains one math symbol.

Would this be an example?

• 2+40÷2• YES!• Why?–It contains more than one math

symbol.

Recall…

• PEMDAS acronym in solving these problems• Parenthesis• Exponent• Multiplication• Division• Addition• Subtraction

Let’s try this one

• 3 + 6 x (5 + 4) ÷ 3 - 7 • PEMDAS• Steps– Parenthesis– Multiplication– Division– Addition– Subtraction

Left to Right Rule

• This says: when you have either multiplication and division or addition and subtraction in a ‘backwards’ order in an expression, you can simply solve them going left to right.

• Sometimes these two pairs of symbols aren’t in the order that the PEMDAS acronym shows us in solving problems.

Here’s an example:

• 9-3x(8÷2)+6• Steps:– Parenthesis– Multiplication– Division– SUBTRACTION– Addition

• We did subtraction before addition by using the Left to Right rule.– So if the division and multiplication signs switched places, we

could use the rule there too.

Now, get together with a partner and try this problem together!

• COPY THIS PROBLEM ON YOUR OWN PAPER!• Define each step you will take in solving the

problem and use the Left to Right rule if needed.

• 9 - 5 ÷ (8 - 3) x 2 + 6²

• Remember: PEMDAS