OK, let's do this. We've got 706616040 and 997305554 and we're adding them all together.

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

Step 2: We'll start by adding the digits 4 & 5 in column 2 and get 9.

Step 3: We'll start by adding the digits 0 & 5 in column 3 and get 5.

Step 4: We'll start by adding the digits 6 & 5 in column 4 and get 11.
We'll write down the last digit 1 and carry the 1 to the next column.

Step 5: We'll start by adding the digits 1 & 0 in column 5 and get 2.

Step 6: We'll start by adding the digits 6 & 3 in column 6 and get 9.

Step 7: We'll start by adding the digits 6 & 7 in column 7 and get 13.
We'll write down the last digit 3 and carry the 1 to the next column.

Step 8: We'll start by adding the digits 0 & 9 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 7 & 9 in column 9 and get 17.
We'll write down the last digit 7 and carry the 1 to the next column.

So, 706616040 + 997305554 = 1703921594.

