We are presented with 836 and 6161. 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 & 6 in column 2 and get 9.

Step 3: We'll start by adding the digits 8 & 1 in column 3 and get 9.

Step 4: We'll start by adding the digits 0 & 6 in column 4 and get 6.

So, 836 + 6161 = 6997.

