Here we go! We're going to add 1155880103 and 7101111391 together.

Step 1: We'll start by adding the digits 3 & 1 in column 1 and get 4.

Step 2: We'll start by adding the digits 0 & 9 in column 2 and get 9.

Step 3: We'll start by adding the digits 1 & 3 in column 3 and get 4.

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

Step 5: We'll start by adding the digits 8 & 1 in column 5 and get 9.

Step 6: We'll start by adding the digits 8 & 1 in column 6 and get 9.

Step 7: We'll start by adding the digits 5 & 1 in column 7 and get 6.

Step 8: We'll start by adding the digits 5 & 0 in column 8 and get 5.

Step 9: We'll start by adding the digits 1 & 1 in column 9 and get 2.

Step 10: We'll start by adding the digits 1 & 7 in column 10 and get 8.

So, 1155880103 + 7101111391 = 8256991494.

