Let's solve this addition problem. We have 1287 and 456, and we need to add them together.

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

Step 2: We'll start by adding the digits 8 & 5 in column 2 and get 14.
We'll write down the last digit 4 and carry the 1 to the next column.

Step 3: We'll start by adding the digits 2 & 4 in column 3 and get 7.

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

So, 1287 + 456 = 1743.

