How to add three-digit numbers
Place one number above the other so the hundreds’ place digits, the tens’ place digits and ones’ place digits are lined up. Draw a line under the bottom number.
Add the two ones’ place digits.
Add the numbers in the tens’ place column and place the answer below the line and to the left of the ones’ place sum.
Add the numbers in the hundreds’ place column and place the answer below the line and to the left of the tens’ place sum.
Learn more about adding on multiples of 100 by reading the explanation below.