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Adding Three-Digit Numbers

The numbers are getting bigger. Now that you have two-digit addition under control, you need to move up and start working with values in the hundreds column (triple-digit numbers). Remember the process and work from right to left. Instead of stopping at the tens column, you'll just have one more to work with. Let's look at some examples with no carrying.
456 + 123 = 579
281 + 715 = 996
809 + 150 = 959

Looking at Carrying Again

Those examples gave you answers less than one thousand (1,000). It should be obvious that many of the three-digit numbers you add will give you a sum that is larger than 1,000. How do you get there? Bring back those carrying skills.

When your column totals are greater than "9" you will need to carry the "1" into the next column to the left. A sum from the ones column that is higher than "9" will force you to carry a "1" to the tens column. If it's in the tens column you will bring it to the hundreds column. And from the hundreds you will move to the thousands. It's the same process that happens with two-digit numbers.

Example:
573 + 769 = ?
(1) Ones column: 3 + 9 =12
(2) Write the "2" and carry the "1."
(3) Tens column: 1 (carried) + 7 + 6 = 14
(4) Write the "4" and carry the "1."
(5) Hundreds column: 1 (carried) + 5 + 7 = 13
(6) Write the "13" and your final answer is "1342."
So...
573 + 769 = 1,342

More Than Three Digits

Now that you know the basics of moving from one column to the next, you should be able to add any two values together. You will always use the same process, start with the column on the right, and move towards the left. When you reach numbers called decimals, the rules will stay the same. You can easily do these problems...
1,234 + 4,231 = 5,465
20,567 + 35,411 = 55,978

RELATED ACTIVITIES

Addition Activity Three-Digit Addtion Quiz (With Carrying)
- Play Activity

Addition Activity Three-Digit Addition Quiz (No Carrying)
- Play Activity


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