Here we go! We're going to add 6001 and 3590 together.

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

Step 2: We'll start by adding the digits 0 & 9 in column 2 and get 9.

Step 3: We'll start by adding the digits 0 & 5 in column 3 and get 5.

Step 4: We'll start by adding the digits 6 & 3 in column 4 and get 9.

So, 6001 + 3590 = 9591.

