Let's solve this addition problem. We have 3358 and 4139, and we need to add them together.

Step 1: We'll start by adding the digits 8 & 9 in column 1 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 5 & 3 in column 2 and get 9.

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

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

So, 3358 + 4139 = 7497.

