We've got two numbers: 2102 and 135. Let's find their sum.

Step 1: We'll start by adding the digits 2 & 5 in column 1 and get 7.

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

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

Step 4: We'll start by adding the digits 2 & 0 in column 4 and get 2.

So, 2102 + 135 = 2237.

