Let's solve this addition problem. We have 1409 and 120, and we need to add them together.

Step 1: We'll start by adding the digits 9 & 0 in column 1 and get 9.

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

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

Step 4: We'll start by adding the digits 1 & 0 in column 4 and get 1.

So, 1409 + 120 = 1529.

