OK, let's do this. We've got 2626 and 2151 and we're adding them all together.

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 2 & 5 in column 2 and get 7.

Step 3: We'll start by adding the digits 6 & 1 in column 3 and get 7.

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

So, 2626 + 2151 = 4777.

