Ready to do some math? We're starting with 870 and 403 and adding them up.

Step 1: We'll start by adding the digits 0 & 3 in column 1 and get 3.

Step 2: We'll start by adding the digits 7 & 0 in column 2 and get 7.

Step 3: We'll start by adding the digits 8 & 4 in column 3 and get 12.
We'll write down the last digit 2 and carry the 1 to the next column.

So, 870 + 403 = 1273.

