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Instructor Overview

Students do a card sort in which they match expressions in words with their equivalent algebraic expressions.

Key Concepts

  • A mathematical expression that uses letters to represent numbers is an algebraic expression.
  • A letter used in place of a number in an expression is called a variable.
  • An algebraic expression combines both numbers and letters using the arithmetic operations of addition (+), subtraction (–), multiplication (·), and division (÷) to express a quantity.
  • Words can be used to describe algebraic expressions.
  • There are conventions for writing algebraic expressions:
    • The product of a number and a variable lists the number first with no multiplication sign. For example, the product of 5 and n is written as 5n, not n5.
    • The product of a number and a factor in parentheses lists the number first with no multiplication sign. For example, write 5(+ 3), not (x + 3)5.
    • For the product of 1 and a variable, either write the multiplication sign or do not write the "1." For example, the product of 1 and z is written either 1 ⋅ z or z, not 1z.

Goals and Learning Objectives

  • Translate between expressions in words and expressions in symbols.