We have numbers 400 and 2570. Let's start adding them together.

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

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

Step 3: We'll start by adding the digits 4 & 5 in column 3 and get 9.

Step 4: We'll start by adding the digits 0 & 2 in column 4 and get 2.

So, 400 + 2570 = 2970.

