Okay, we are given 8254 and 143. Let's add them up step by step.

Step 1: We'll start by adding the digits 4 & 3 in column 1 and get 7.

Step 2: We'll start by adding the digits 5 & 4 in column 2 and get 9.

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

Step 4: We'll start by adding the digits 8 & 0 in column 4 and get 8.

So, 8254 + 143 = 8397.

