We've got two numbers: 4006 and 4870. Let's find their sum.

Step 1: We'll start by adding the digits 6 & 0 in column 1 and get 6.

Step 2: We'll start by adding the digits 0 & 7 in column 2 and get 7.

Step 3: We'll start by adding the digits 0 & 8 in column 3 and get 8.

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

So, 4006 + 4870 = 8876.

