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Liu Guanyi had lived for hundreds of years and achieved many great achievements that most people couldn't even hope to comprehend, let alone reach.
He definitely had many heaps of life experience, but having a rich life experience didn't mean that he was proficient in every single discipline of knowledge.
Even if Liu Guanyi was, considering how backward his civilization was compared to the tower, he would still be lacking in the understanding of many disciplines of knowledge since humans and civilization were always continued to advance alongside each other.
Furthermore, there could be many new disciplines that weren't available in his previous world.
To put it simply, Liu Guanyi instantly felt a growing headache as he stared at the square boxes with numbers and cursed in his heart. He was ready to face any monsters but he wasn't ready to face such a monstrosity.
'Damn it, what is this?! Has mathematics really advanced so much?' Liu Guanyi cursed inwardly.
Looking at the small boxes and numbers, Liu Guanyi knew that it was related to mathematics somehow. Unfortunately, he didn't know what the relation was. It wasn't because he was bad at mathematics, not at all.
He could do subtraction and addition, as well as multiplication and division, something that most people in his previous world couldn't do.
It was impressive considering his background as a martial warrior and that most warriors wouldn't even bother learning a complicated discipline such as mathematics.
Unfortunately for Liu Guanyi, he had to admit that his "impressive" understanding of mathematics wasn't actually just bad. It was awfully terrible compared to the natives of the tower.
Liu Guanyi turned to look at Xin by his side. "Xin, can you solve this puzzle? I am not good at mathematics nor I am familiar with this puzzle, but you can do it, right?"
"Well, if you say so Mr. Liu, let me take a look at it first." Xin stepped forward to look at the puzzle more closely and attentively.
Seeing the number and arrangement of the squares with a certain number inside every square, Xin put his finger on his chin and rubbed it as he pondered seriously.
'Nine squares arranged in the form of three rows and columns with nine smaller boxes inside each square arranged in the same way, and there's a number in every box which differed from one another.' Xin studied the boxes and numbers more closely.
'Hmm? Not all of the boxes are filled with numbers. Wait, I think… I have seen this game somewhere.' Xin rejoiced inwardly.
"I think I can do it, Mr. Liu. If I'm not wrong, we only have to fill up the blank boxes according to the existing numbers in some of the boxes." After observing the puzzle for a while, Xin finally said with confidence.
"That's good if you are confident."
Xin smiled smugly hearing the praise. "Of course! I have seen someone play this game. If they can do it, I certainly can do the same, if not better."
He put his finger on a certain box and dragged it toward another box. "Let's see… since there's number three in this column and another number three in this row, there is only a single way to fill up this blank box here… another number three."
"Now, with that solved, we will be able to guess the box… here." After a moment of deliberation, Xin put his finger on an empty box in line with a few more number three's.
"There are already three boxes with number three in line with this so it's easy, just put another one. I am smart, aren't I?" Xin smirked as he looked toward Liu Guanyi with a smug face.
"Nice one, Xin! Just keep it up."
"Alright, Mr. Liu, just watch me finish this puzzle in a blink of an eye." Xin focused on the square again, trying to find similar numbers to get the clues which got him an easy answer. "Now, which one is the empty box I can fill up again?"
Xin scanned the numbers without blinking, however, even after a few minutes of silence, he didn't find any more than one number which lined up to the same number.
"How is it, Xin? Did you get the answer? It's been a few minutes."
Scratching his head, Xin said with a hesitant voice. "Umm, I'm sorry, Mr. Liu. I can't find it anymore, there are no similar numbers in line in the boxes."
"Well, don't give up yet. Try to remember it again, maybe there is another way to solve the puzzle." Liu Guanyi tried to encourage him. He had no idea at all so he could only rely on Xin, who at least had some knowledge about the puzzle to solve it.
Minutes passed quickly as they tried to figure out the way to solve the vexing puzzle. They tried many ways, filling up the empty boxes with random numbers, arranging numbers one to nine in a row and column, and even trying to break the door forcefully with their combined power, only to harm their own bodies as the gate withstood it without any scratch.
Breaking the gate or cheating was impossible. Liu Guanyi guessed that the gate was probably reinforced with a spell just like anywhere in the Hell Train. More than one hour was already wasted as they sat down near the gate.
Letting out a sigh, Liu Guanyi looked at the dejected boy. "Xin, go send a message to princess Adori to come here. I guess this time we have to trouble her again."
"No need, Mr. Liu, I already sent her a message and our location the moment I couldn't solve the puzzle." Xin spoke with a sad but firm voice.
"Oh?" Liu Guanyi was slightly surprised. "She likes to annoy you sometimes and likely won't let this chance to slip away but you took the initiative to contact her on your own?"
Shaking his head, Xin replied with a neutral tone. "It doesn't matter even if she teases and mocks me. Rather than focusing on myself, I should prioritize the team."
Xin's mouth curled up as he looked at him. "Furthermore, it's not like you will also be let off, Mr. Liu."
Liu Guanyi smiled. "That's true, but seriously, you have really grown up, Xin."
Suddenly, a gust of wind blew their faces as thick, lustrous silver-white hair fluttered right in front of him. "So, why did you call me so suddenly?"
Your powerstones, please?