We've got two numbers: 2101 and 4011. Let's find their sum.

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

Step 2: We'll start by adding the digits 0 & 1 in column 2 and get 1.

Step 3: We'll start by adding the digits 1 & 0 in column 3 and get 1.

Step 4: We'll start by adding the digits 2 & 4 in column 4 and get 6.

So, 2101 + 4011 = 6112.

