OK, let's do this. We've got 400 and 2374 and we're adding them all together.

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

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 & 3 in column 3 and get 7.

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

So, 400 + 2374 = 2774.

