Okay, we are given 1011 and 8715. Let's add them up step by step.

Step 1: We'll start by adding the digits 1 & 5 in column 1 and get 6.

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

Step 3: We'll start by adding the digits 0 & 7 in column 3 and get 7.

Step 4: We'll start by adding the digits 1 & 8 in column 4 and get 9.

So, 1011 + 8715 = 9726.

