We are presented with 1563 and 1003. Let's work out the sum.

Step 1: We'll start by adding the digits 3 & 3 in column 1 and get 6.

Step 2: We'll start by adding the digits 6 & 0 in column 2 and get 6.

Step 3: We'll start by adding the digits 5 & 0 in column 3 and get 5.

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

So, 1563 + 1003 = 2566.

