We have numbers 3970 and 1566. Let's start adding them together.

Step 1: We'll start by adding the digits 0 & 6 in column 1 and get 6.

Step 2: We'll start by adding the digits 7 & 6 in column 2 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 9 & 5 in column 3 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 3 & 1 in column 4 and get 5.

So, 3970 + 1566 = 5536.

