We have numbers 2921 and 6972. Let's start adding them together.

Step 1: We'll start by adding the digits 1 & 2 in column 1 and get 3.

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

Step 3: We'll start by adding the digits 9 & 9 in column 3 and get 18.
We'll write down the last digit 8 and carry the 1 to the next column.

Step 4: We'll start by adding the digits 2 & 6 in column 4 and get 9.

So, 2921 + 6972 = 9893.

