Summary: Multiplying and Dividing Integers

Key Concepts

  • Multiplication of Signed Numbers
    • To determine the sign of the product of two signed numbers:
      Same Signs Product
      Two positives

      Two negatives

      Positive

      Positive

      Different Signs Product
      Positive • negative

      Negative • positive

      Negative

      Negative

  • Division of Signed Numbers
    • To determine the sign of the quotient of two signed numbers:
      Same Signs Quotient
      Two positives

      Two negatives

      Positive

      Positive

      Different Signs Quotient
      Positive • negative

      Negative • Positive

      Negative

      Negative

  • Multiplication by [latex]-1[/latex]
    • Multiplying a number by [latex]-1[/latex] gives its opposite: [latex]-1(a)=-a[/latex]
  • Division by [latex]-1[/latex]
    • Dividing a number by [latex]-1[/latex] gives its opposite: [latex]a\div(-1)=-a[/latex]