We are presented with 6436 and 3211. Let's work out the sum.

Step 1: We'll start by adding the digits 6 & 1 in column 1 and get 7.

Step 2: We'll start by adding the digits 3 & 1 in column 2 and get 4.

Step 3: We'll start by adding the digits 4 & 2 in column 3 and get 6.

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

So, 6436 + 3211 = 9647.

