We are presented with 5128 and 9107. Let's work out the sum.

Step 1: We'll start by adding the digits 8 & 7 in column 1 and get 15.
We'll write down the last digit 5 and carry the 1 to the next column.

Step 2: We'll start by adding the digits 2 & 0 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 5 & 9 in column 4 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

So, 5128 + 9107 = 14235.

