We are presented with 2835 and 5023. Let's work out the sum.

Step 1: We'll start by adding the digits 5 & 3 in column 1 and get 8.

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 8 & 0 in column 3 and get 8.

Step 4: We'll start by adding the digits 2 & 5 in column 4 and get 7.

So, 2835 + 5023 = 7858.

