Okay, we are given 7431 and 1426. Let's add them up step by step.

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

Step 2: We'll start by adding the digits 3 & 2 in column 2 and get 5.

Step 3: We'll start by adding the digits 4 & 4 in column 3 and get 8.

Step 4: We'll start by adding the digits 7 & 1 in column 4 and get 8.

So, 7431 + 1426 = 8857.

