Even though the Simple Puzzle in seems easy to solve at first, the right solution can be difficult to find at first. You have to input a code based on a pattern established by the combination of other shown numbers.
Solving the Simple Puzzle will let you earn a few rewards and give you a good idea of what other puzzles might look like later in the game.
The Simple Puzzle is an available side objective from the Bulletin Board offered by a client who offers a special prize to whoever can find the right solution.
When you accept the request, travel to the entrance of the Presence Chamber and interact with the monitor located on the pillar on your right.
You can always fast travel in to this area to get to the puzzle quickly. The client will offer three different examples of number combinations leading to a correct code.