We are presented with 1742 and 7123. Let's work out the sum.

Step 1: We'll start by adding the digits 2 & 3 in column 1 and get 5.

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

Step 3: We'll start by adding the digits 7 & 1 in column 3 and get 8.

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

So, 1742 + 7123 = 8865.

