We are presented with 4254 and 4004. Let's work out the sum.

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

Step 2: We'll start by adding the digits 5 & 0 in column 2 and get 5.

Step 3: We'll start by adding the digits 2 & 0 in column 3 and get 2.

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

So, 4254 + 4004 = 8258.

