Okay, we are given 1117 and 1670. Let's add them up step by step.

Step 1: We'll start by adding the digits 7 & 0 in column 1 and get 7.

Step 2: We'll start by adding the digits 1 & 7 in column 2 and get 8.

Step 3: We'll start by adding the digits 1 & 6 in column 3 and get 7.

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

So, 1117 + 1670 = 2787.

