We've got two numbers: 6915 and 4050. Let's find their sum.

Step 1: We'll start by adding the digits 5 & 0 in column 1 and get 5.

Step 2: We'll start by adding the digits 1 & 5 in column 2 and get 6.

Step 3: We'll start by adding the digits 9 & 0 in column 3 and get 9.

Step 4: We'll start by adding the digits 6 & 4 in column 4 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

So, 6915 + 4050 = 10965.

