Okay, we are given 3726 and 4949. Let's add them up step by step.

Step 1: We'll start by adding the digits 6 & 9 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 2 & 4 in column 2 and get 7.

Step 3: We'll start by adding the digits 7 & 9 in column 3 and get 16.
We'll write down the last digit 6 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 3 & 4 in column 4 and get 8.

So, 3726 + 4949 = 8675.

