in an earlier video sal said that the orders of operations was “PEMDAS” was this not confusing to anyone else? all alone i though that it was “BEDMAS”

They mean the same thing. There are multiple acronyms used to help students remember the order of operations rules. The differences seem to be somewhat by country (where someone lives). Besides PEMDAS and BEDMAS, there are several others including BIDMAS, BODMAS, GEMS. Here's how BEDMAS & PEMDAS line up together so you can see, there is no difference: B=Brackets / P= Parentheses. Both refer to grouping symbols. You need to do the any work inside grouping symbols as your first step. E=Exponents. Exponents are done as the 2nd step. DM or MD = Multiply & Divide. These are in one rule/step. You need to do these operations from left to right. AS = Add / Subtract. Again, these operations are done from left to right. Hope this helps.

Main content

Course: Algebra (all content) > Unit 1

Lesson 4: Evaluating expressions word problems

Evaluating expressions review

Google Classroom

An algebraic expression like 3x can be evaluated for any value of x. Say x=4, then 3x = 3*4 = 12. In this article, we review how to evaluate algebraic expressions.

What does it mean to evaluate an algebraic expression?

An algebraic expression like

2 x + 3

can be evaluated by substituting a value for

x

. For example, if

x = 4

then:

\begin{aligned} 2 x + 3 \\ = & 2 \cdot 4 + 3 \\ = & 8 + 3 \\ = & 11 \end{aligned}

We can also evaluate more complicated expressions that have more than one variable. For example, we can evaluate

10 + 2 p - 3 r

when

p = 4

and

r = 5

\begin{aligned} 10 + 2 p - 3 r \\ = & 10 + 2 \cdot 4 - 3 \cdot 5 \\ = & 10 + 8 - 15 \\ = & 3 \end{aligned}

Want to learn more about evaluating expressions? Check out this video. And here's a word problem video if you're curious how this concept might apply to the real world.

Practice

Problem 1

Evaluate the expression $7 + 4 b$ ‍ when $b = 3$ ‍.

Want more practice like this? Check out this basic exercise and this more advanced exercise.

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Nava, Hector
Posted 7 years ago. Direct link to Nava, Hector's post “the last question was a l...”
the last question was a little hard
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nanncie7
Posted 8 years ago. Direct link to nanncie7's post “I need help to do my exer...”
I need help to do my exercice
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Juliana Smith
Posted 5 years ago. Direct link to Juliana Smith's post “in an earlier video sal s...”
in an earlier video sal said that the orders of operations was “PEMDAS” was this not confusing to anyone else? all alone i though that it was “BEDMAS”
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- Kim Seidel
  Posted 5 years ago. Direct link to Kim Seidel's post “They mean the same thing....”
  They mean the same thing. There are multiple acronyms used to help students remember the order of operations rules. The differences seem to be somewhat by country (where someone lives). Besides PEMDAS and BEDMAS, there are several others including BIDMAS, BODMAS, GEMS.
  
  Here's how BEDMAS & PEMDAS line up together so you can see, there is no difference:
  
  B=Brackets / P= Parentheses. Both refer to grouping symbols. You need to do the any work inside grouping symbols as your first step.
  
  E=Exponents. Exponents are done as the 2nd step.
  
  DM or MD = Multiply & Divide. These are in one rule/step. You need to do these operations from left to right.
  
  AS = Add / Subtract. Again, these operations are done from left to right.
  
  Hope this helps.
  Comment on Kim Seidel's post “They mean the same thing....”
  (4 votes)
Utkarsh Priyadarshi
Posted a year ago. Direct link to Utkarsh Priyadarshi's post “This is so interesting,Id...”
This is so interesting,Idk why I didnt study these things properly in high school
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Kdog21869
Posted 7 years ago. Direct link to Kdog21869's post “OK PLEASE give me somethi...”
OK PLEASE give me something harder
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kenneth.148614
Posted 8 months ago. Direct link to kenneth.148614's post “How do i add whole number...”
How do i add whole number by decimals
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- @sulaf🎶
  Posted 5 months ago. Direct link to @sulaf🎶's post “you just add the whole nu...”
  you just add the whole number to the number before the point, and then you just add the decimal number behind the point.
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Jeremiah Flores
Posted 4 years ago. Direct link to Jeremiah Flores's post “3x3x3x3x3x3/3x3x3x3 rewr...”
3x3x3x3x3x3/3x3x3x3 rewrite as 3 exponent n ?
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- DiyaP
  Posted 3 years ago. Direct link to DiyaP's post “No it would be 3 to the p...”
  No it would be 3 to the power of 6 and 3 to the power of 4
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Ruchitha Bandaru
Posted 7 years ago. Direct link to Ruchitha Bandaru's post “what does ^ mean”
what does ^ mean
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- boleandrew608
  Posted 6 months ago. Direct link to boleandrew608's post “^ means superscript or ex...”
  ^ means superscript or exponents
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hkworkm1
Posted 6 years ago. Direct link to hkworkm1's post “What is the perimeter of ...”
What is the perimeter of a square with a side length of \dfrac57
7
5
start fraction, 5, divided by, 7, end fraction units?
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(1 vote)
Answer
- Kim Seidel
  Posted 6 years ago. Direct link to Kim Seidel's post “Perimeter means you need ...”
  Perimeter means you need the distance around the outside edge of the square - add up all sides. Squares have 4 equal sides. And, your square has a side length of 5/7.
  Perimeter = 5/7 + 5/7 + 5/7 + 5/7
  or
  Perimeter = 4 (5/7)
  
  Hope this helps.
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Brianna Vega
Posted 7 years ago. Direct link to Brianna Vega's post “The expression 4x4x4, x g...”
The expression 4x4x4, x gives the perimeter of a square with a side length of xxx units.
What is the perimeter of a square with a side length of \dfrac57
7

5
start fraction, 5, divided by, 7, end fraction units?
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