We are presented with 5595221961 and 5711476940. Let's work out the sum.

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

Step 2: We'll start by adding the digits 6 & 4 in column 2 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 9 & 9 in column 3 and get 19.
We'll write down the last digit 9 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 1 & 6 in column 4 and get 8.

Step 5: We'll start by adding the digits 2 & 7 in column 5 and get 9.

Step 6: We'll start by adding the digits 2 & 4 in column 6 and get 6.

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 9 & 1 in column 8 and get 10.
We'll write down the last digit 0 and carry the 1 to the next column.

Step 9: We'll start by adding the digits 5 & 7 in column 9 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 10: We'll start by adding the digits 5 & 5 in column 10 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

So, 5595221961 + 5711476940 = 11306698901.

