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Expressions and Variables
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- Variable: A letter or symbol that can stand for one or more numbers.
- Expression: A mathematical phrase that includes numbers and variables. These do not have equal signs. Different types of expressions include numerical expressions, algebraic expressions, and word expressions.
Evaluate each expression:
13 × 30 =
390
Evaluate each expression:
14 × 20 =
280
Evaluate each expression:
n - 9, for n = 12
- 12 − 9 =
3
Evaluate each expression:
x + 5, for x = 6
- 6 + 5 =
11
Evaluate each expression:
12 - m, for m = 3
- 12 − 3 =
9
Evaluate each expression:
s ÷ t, for s = 21 and t = 3
- 21 ÷3 =
7
Evaluate each expression:
x ÷ y, for x = 42 and y = 6
- 42 ÷6 =
7
Evaluate each expression:
m ÷ n, for m = 81 and n = 9
- 81 ÷9 =
9
Evaluate each expression:
cd, for c = 4 and d = 8
- (4)(8) =
32
Evaluate each expression:
xy,for x = 9 and y = 8
- (9)(8) =
72
*These practice questions are only helpful when you work on them offline on a piece of paper and then use the solution steps function to check your answer.
Answer
Expressions and Variables
Lecture Slides are screen-captured images of important points in the lecture. Students can download and print out these lecture slide images to do practice problems as well as take notes while watching the lecture.






























0 answers
Post by Kelly Gustafson on February 15, 2011
This is great for a Mother that has gone back to school after many years!
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Post by Romie Rincon on February 25, 2011
45 and going back to school next month...Educator is going to be a great help!! Thanks!!
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Post by Suzanne Keisling Wantland on March 27, 2011
This is awesome for a homeschool parent also!!
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Post by Thomas James Hanrahan on April 26, 2011
Wow! Something professed to be so difficult(Elementary-High School etc.) is explained in simplicity at it's finest! Great reminders of beginnings of math now approaching University Calculus I, begin at the beginning to see if any steps in the process of learning advanced math (algebraic, calculus and otherwise) require microscopic review. Kudos and Thanks for your website. As utilization is confirmed progressively, I will purchase subsequent months subscriptions throughout my pursuit of a Bachelors Degree, Majoring in Computer Science.
TJH
1 answer
Last reply by: Wasay Ahmad
Wed Jan 9, 2013 4:22 PM
Post by judy lee on August 15, 2011
This has great point of explaning Expressions and Variables!!!!!
But the voice is too small to hear.
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Post by julius mogyorossy on August 27, 2011
Word of advice, before you watch a lesson read the comments by your fellow students, they will point out mistakes that were made, to keep you from feeling insane, if you see something where they act like it was explained earlier but you think it wasn't, you are not crazy, don't worry, they will explain it later, it seems some of the videos were put in the wrong order.
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Post by Javon Roberts on September 3, 2011
I love you Mary, lol. That's all I can say. This is extremely helpful!!
1 answer
Fri Feb 3, 2012 11:41 PM
Post by Alexzander s on November 20, 2011
Why cant you do all the videos for math (or at least up to high school math)? The other teachers sound like they're on 5 hour energy to get through each lecture when you sound so calm.
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Post by ozgur kuzu on December 19, 2011
she is great teacher :)
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Post by Senghuot Lim on December 22, 2011
anybody else have an apple as their icon then my username is 7seng7
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Post by Jerome Plescia on February 4, 2012
Great video
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Post by Mya McCulloch on July 6, 2012
Educator.com is a great place to learn.
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Post by Abdihakim Ibrahim on July 14, 2012
i loved this!
educator is cool
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Post by Abdiker Mohamud on November 29, 2012
This very calm and cool way to explain the task on hand. Good job, and as they say do it all the way through High school math
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Post by success3 on April 29 at 10:03:13 AM
I LOVE YOU MARY