Lesson 1: Standard Addition Algorithm and Regrouping

Property

To add whole numbers:
Step 1. Write the numbers so each place value lines up vertically.
Step 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.
Step 3. Continue adding each place value from right to left, adding each place value and carrying if needed.

Examples

• For $481 + 352$, add the ones: $1+2=3$. Add the tens: $8+5=13$. Write 3, carry 1. Add the hundreds: $1+4+3=8$. The sum is $833$.

Property

When adding three or more numbers, if the sum of the digits in a column is a two-digit number (e.g., 24), write the ones digit (4) in the sum and regroup (carry) the tens digit (2) to the next place value column.

Examples