Rule of Addition For 3 Digit Numbers

The rule for adding three-digit numbers is similar to adding smaller numbers but involves more digits. Here’s a step-by-step breakdown of how to add two three-digit numbers.

Step 1: Align the Numbers

• Write the two numbers one under the other, aligning them by their place values (hundreds, tens, and ones).
• Make sure the digits in the ones place, tens place, and hundreds place are directly above or below each other.

Step 2: Start Adding from the Right

• Begin with the Ones Column: Add the digits in the ones place. If the sum is 10 or greater, write down the digit in the ones place and carry over the digit in the tens place to the next column.
• Move to the Tens Column: Add the digits in the tens place, including any number we carried over from the ones column. If this sum is 10 or greater, write down the digit in the tens place and carry over the digit in the hundreds place to the next column.
• Finish with the Hundreds Column: Add the digits in the hundreds place, including any number we carried over from the tens column. Write down the result in the hundreds place.

Step 3: Write Down the Result

• After we have added all the columns, write down the final result, which is the sum of the two three-digit numbers.

Example:

Let’s add 482 and 369.

  482
+ 369
------

1. Ones place: 2 + 9 = 11. Write down 1 in the ones place and carry over 1 to the tens place.
2. Tens place: 8 + 6 + 1 (carried over) = 15. Write down 5 in the tens place and carry over 1 to the hundreds place.
3. Hundreds place: 4 + 3 + 1 (carried over) = 8. Write down 8 in the hundreds place.

So, the sum is 851.

  482
+ 369
------
  851

This is the basic rule of addition for three-digit numbers.