We've got two numbers: 7002 and 1897. Let's find their sum.

Step 1: We'll start by adding the digits 2 & 7 in column 1 and get 9.

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 0 & 8 in column 3 and get 8.

Step 4: We'll start by adding the digits 7 & 1 in column 4 and get 8.

So, 7002 + 1897 = 8899.

