OK, let's do this. We've got 307 and 9111 and we're adding them all together.

Step 1: We'll start by adding the digits 7 & 1 in column 1 and get 8.

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 3 & 1 in column 3 and get 4.

Step 4: We'll start by adding the digits 0 & 9 in column 4 and get 9.

So, 307 + 9111 = 9418.

