We've got two numbers: 9634 and 7840. Let's find their sum.

Step 1: We'll start by adding the digits 4 & 0 in column 1 and get 4.

Step 2: We'll start by adding the digits 3 & 4 in column 2 and get 7.

Step 3: We'll start by adding the digits 6 & 8 in column 3 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 9 & 7 in column 4 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

So, 9634 + 7840 = 17474.

