Variable and Open Sentences Mrs. Muyard – 5 th Grade SSES

What is a variable?:

What is a variable? A variable is a symbol that represents an unknown value in a math sentence. Usually a variable is a letter from the alphabet (like x) but it can also be a shape.

Example:

Example Charlie had some bones hidden in his doghouse. He hid 3 more bones yesterday and now he has a total of 8 bones in his doghouse. How many bones were in the house before? Some number plus 3 more gives us 8 X + = 8 3

Other ways to show variable expressions:

Other ways to show variable expressions 3 + N 7b Y - 9 25 + h K 2 5 x L

Blackbeard’s Gold:

Blackbeard’s Gold Click here if the video will not open

Practice:

Practice 5 more than a number 14 less than a number A number times 20 A number divided by 2 5 + k 14 – f Y x 20 X 2

PowerPoint Presentation:

Quiz Time!

Question 1:

Question 1 Which variable expression shows “8 more than a number”? 8 + n 8 - n 8 x n 8/n

Question 2:

Question 2 There were 10 ducks swimming in the pond. Some flew away. Which expression represents the ducks? 10 + d 10 – d 10 x d 10/d

Question 3:

Question 3 Charlie was playing cards. He split them into 5 equal groups. Which expression represents the situation? C + 5 C – 5 C x 5 C/5

Question 4:

Question 4 Each 5 th grade class at SSES has the same number of students. There are 6 classes. Which expressions represents the situation? S + 6 S – 6 S x 6 S/6

Question 5:

Question 5 Charlie has 150 bones. He gives some away to his neighbors. Which expression represents this situation? 150 + b 150 – b 150 x b 150/b

Online Practice Games:

Online Practice Games Solve to X – this is a timed game! You are racing to see how many times you can solve to x in a minute. Who Wants to be a Millionaire – See how far you can get in the algebra version of this game show!

Sources:

Sources Discovery Studios (Producer). (2006). Example 2: Equations Using Variables--Paris Population . [Video Segment]. Available from http://www.discoveryeducation.com/

PowerPoint Presentation:

Rock On!!!!

PowerPoint Presentation:

Wrong!

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