Addition is one of the four basic operations in mathematics. When we add numbers, we combine their values to find a total, called the sum.

To add numbers, start with the ones place and work left. If a column adds to 10 or more, write the ones digit below the line and carry the tens digit to the next column. This process is called regrouping.

Addition has useful properties. The commutative property tells us that 3 + 5 gives the same result as 5 + 3. The associative property tells us that (2 + 3) + 4 equals 2 + (3 + 4). The identity property tells us that adding zero to any number leaves it unchanged.

Word problems require you to identify what is being combined. Look for clue words like "total," "altogether," "combined," "in all," and "how many more." Set up the addition expression, solve carefully, and check that your answer makes sense in context.