Okay, we are given 1287 and 2029. Let's add them up step by step.

Step 1: We'll start by adding the digits 7 & 9 in column 1 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 8 & 2 in column 2 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 2 & 0 in column 3 and get 3.

Step 4: We'll start by adding the digits 1 & 2 in column 4 and get 3.

So, 1287 + 2029 = 3316.

