Summary: Adding Whole Numbers

Key Concepts

  • Addition Notation To describe addition, we can use symbols and words.
    Operation Notation Expression Read as Result
    Addition [latex]+[/latex] [latex]3+4[/latex] three plus four the sum of [latex]3[/latex] and [latex]4[/latex]
  • Identity Property of Addition
    • The sum of any number [latex]a[/latex] and [latex]0[/latex] is the number.
      • [latex]a+0=a[/latex]
      • [latex]0+a=a[/latex]
  • Commutative Property of Addition
    • Changing the order of the addends [latex]a[/latex] and [latex]b[/latex] does not change their sum. [latex]a+b=b+a[/latex] .
  • Add whole numbers.
    1. Write the numbers so each place value lines up vertically.
    2. Add the digits in each place value. Work from right to left starting with the ones place. If a sum in a place value is more than 9, carry to the next place value.
    3. Continue adding each place value from right to left, adding each place value and carrying if needed.


sum   The sum is the result of adding two or more numbers.