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Adding Three Digit Numbers

Adding three-digit numbers is similar to adding two-digit numbers, but this time we have to pay attention to the hundreds, tens, and ones.

For example, let's say we want to add the numbers 123 and 456. We will line them up just like before, but this time we will have to pay attention to the hundreds, tens, and ones.

    123
 +456

Now, we will start by adding the ones, which are the last digits of the numbers, 3 and 6. So 3 + 6 = 9. So we write 9 under the line.

   123
 +456
       9

Next, we will move on to the tens, which are the middle digits of the numbers, 2 and 5. So 2 + 5 = 7. And we write 7 in front of the 9, like this:

   123
 +456
     79

Finally, we will add the hundreds, which are the first digits of the numbers, 1 and 4. So 1 + 4 = 5. And we write 5 in front of the 79, like this:

   123
 +456
    579

And that's it! We have added the three-digit numbers 123 and 456 and got the answer 579.

Carrying

Just like when we add two-digit numbers, sometimes when we add three-digit numbers, we might get a bigger number than 9 for the ones, tens or hundreds. This is called "carrying."

For example, let's say we want to add the numbers 123 and 789. We will start by adding the ones, 3 + 9 = 12. But since we can only write one digit in that spot, we have to carry the 2 to the tens.

   123
 +789
       2
Now, we will add the tens, 2 + 8 + 2 (carried over) = 12. And we write 2 in front of the 12.

   123
 +789
     12

Next, we will add the hundreds, 1 + 7 +1 (carried over) = 9. And we write 9 in front of the 12, like this:

   123
 +789
    912

And that's it! We have added the three-digit numbers 123 and 789 and got the answer 912.



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