Okay, we are given 1646 and 3146. Let's add them up step by step.

Step 1: We'll start by adding the digits 6 & 6 in column 1 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 4 & 4 in column 2 and get 9.

Step 3: We'll start by adding the digits 6 & 1 in column 3 and get 7.

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

So, 1646 + 3146 = 4792.

