Essential Ideas
Section 2.2: Addition of Integers

  • The set of integers is the set {..., -4, -3, -2, -1, 0, 1, 2, 3, 4, }.
  • The symbol "-" means minus or subtraction when it comes between two numbers, two variables, two expressions or between combinations of those, as in 7 10. It means negative when it comes before a number, as in 10. Finally, it means opposite when it comes before a variable, a parentheses or an operation as in -(10).

  • Order Symbols
    Less than (symbol <) means to the left on a number line.
    Greater than (symbol >) means to the right on a number line.
    Equal to (symbol =) means the same point on a number line.

  • Absolute Value
    The absolute value of a number is the distance of that number from 0 on the number line.

  • Evaluate
    To evaluate an absolute value means to write it without absolute value symbols.

  • Procedure for Adding Integers
    Sign of SumAbsolute Values

    This procedure can be summarized in what is called flowchart form.

    Flowchart for the addition of two integers