We've got two numbers: 1534 and 2423. Let's find their sum.

Step 1: We'll start by adding the digits 4 & 3 in column 1 and get 7.

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

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

Step 4: We'll start by adding the digits 1 & 2 in column 4 and get 3.

So, 1534 + 2423 = 3957.

