We are presented with 3143 and 6712. Let's work out the sum.

Step 1: We'll start by adding the digits 3 & 2 in column 1 and get 5.

Step 2: We'll start by adding the digits 4 & 1 in column 2 and get 5.

Step 3: We'll start by adding the digits 1 & 7 in column 3 and get 8.

Step 4: We'll start by adding the digits 3 & 6 in column 4 and get 9.

So, 3143 + 6712 = 9855.

