The sum of numbers with more than one digit can be found by adding each column from right to left, starting with the ones place.
Step 1: Write the second number under the first number so that the ones, tens, and hundreds places are lined up.
Step 2: Add the ones column (3 + 4 = 7). Write the 7 in the ones place of the sum.
Step 3: Add the tens column (5 + 7 = 12). Since 12 has two digits, both digits won't fit in the tens place. So, write the 2 in the tens place of the sum, and carry the 1 to the hundreds column. This is called regrouping.
Step 4: Add the hundreds column (1 + 2 + 1 = 4). Write the 4 in the hundreds place of the sum.