C2.1 Identify and use symbols as variables in expressions and equations.

Activity 1: Determining and Using Symbols in a Relationship


  • Read the following scenario to students:

A cabinetmaker wants to make chairs. He needs legs for the chairs.

  • Ask students to write an algebraic expression that represents the statement.
  • Ask questions such as:
  • What are the unknown quantities? How do you know?
  • What is the constant quantity? What are the variables? Justify your answer.
  • What symbols can be used to represent the variables?

Activity 2: Determining and Using Symbols to Represent Unknown Quantities


  • Present students with the following scenario:

The school's physical education teacher is organizing a volleyball tournament for students in Grades 4-6 . To do this, he needs to know how many students in each grade will be participating. He knows that there are 92 students in Grade 4 and 102 students in Grade 6 , for a total of 300 students. He has yet to determine the number of students in Grade 5.

  • Ask students to write an equation that represents this situation.