We've got two numbers: 5158 and 3506. Let's find their sum.

Step 1: We'll start by adding the digits 8 & 6 in column 1 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 5 & 0 in column 2 and get 6.

Step 3: We'll start by adding the digits 1 & 5 in column 3 and get 6.

Step 4: We'll start by adding the digits 5 & 3 in column 4 and get 8.

So, 5158 + 3506 = 8664.

