We've got two numbers: 7105 and 12. Let's find their sum.

Step 1: We'll start by adding the digits 5 & 2 in column 1 and get 7.

Step 2: We'll start by adding the digits 0 & 1 in column 2 and get 1.

Step 3: We'll start by adding the digits 1 & 0 in column 3 and get 1.

Step 4: We'll start by adding the digits 7 & 0 in column 4 and get 7.

So, 7105 + 12 = 7117.

