Variable and Open Sentences: 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!