Alright, let's solve this problem step by step. We have 1021 and 6157 and we're adding them together.

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

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

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

Step 4: We'll start by adding the digits 1 & 6 in column 4 and get 7.

So, 1021 + 6157 = 7178.

