#### Chapter 7 - Numerical Puzzle

After confirming that the Yu Hanjiang who refreshed the 2 of Heart’s world record was the person he knew, Xiao Lou opened his mouth and asked, “This Yu Hanjiang, how do I add him as a friend?”

A of Hearts smiled. “There is no such thing as adding friends in the Card World.”

Xiao Lou changed his words. “How do I team up with him to clear the instance?”

A of Hearts patiently explained, “If you want to challenge a secret room with someone, you must find the secret room keeper to buy a contract and establish a contractual relationship with the person you want to team up with. In this way, you will be bound together for future secret rooms. If he opens a new secret room, you will be pulled into the secret room. Similarly, if you open a room then you will pull him into the secret world where you are.”

“How much is the contract?”

“Buying a contract requires the consumption of gold coins that can be obtained in the process of clearing the instance. Try and earn them from the subsequent secret rooms.”

Hearing the answer from the keeper, Xiao Lou helplessly pinched his eyebrows. The currency in this world was ‘gold coins’ and he was currently penniless. He had to wait to buy the contract for the team since he couldn’t afford it at all. What’s more, the D-grade secret rooms were single-player. There was no way to form a team. He could only wait until he earned money later.

Knowing that Yu Hanjiang had also come to the Card World, Xiao Lou’s mood was quite complicated.

In this strange Card World, he should be happy to meet a familiar person.

However, he came to this world because of a car accident. It was likely that Group Leader Yu also came to this world as an accident. In the real world, Yu Hanjiang might’ve died.

Thinking of the young criminal policeman who had solved countless unsolved cases, Xiao Lou felt very sorry.

What had happened to Group Leader Yu? No wonder why he never returned the WeChat that day.

In any case, since they were reborn into this world, the only thing they could do was live.

He thought that it would be no problem to survive the C-grade secret rooms with Yu Hanjiang’s skills.

It was possible to form a team after going to the C-grade rooms. At that time, he would find a way to earn some gold coins, buy a contract book and then find Yu Hanjiang to clear the Hearts room. Since there was a professional criminal investigation master such as Yu Hanjiang, the murderers in the world of Hearts wouldn’t be able to hide.

Xiao Lou put away his thoughts and spoke calmly, “Continue to break through.”

The moment he finished speaking, the 2 of Diamonds card that he already extracted emitted a familiar red light. A strange force surrounded his body and he was sucked into the card room.

***

It was a dim enclosed space that was only four square metres inside. This meant people would feel cramped just taking two steps.

The light in the entire chamber came from an open flashlight hanging in a corner. Next to the flashlight was a pendulum clock and the hour hand pointed to 19:00.

The moment Xiao Lou entered the space, the pendulum clock started swinging regularly with a clear ‘tick’ sound.

A text prompt popped up in the suspension box.

[Welcome to the 2 of Diamonds room, ‘Numerical Puzzle.’]

[Please find the mechanisms at the fastest speed, crack the password and open all the password locks.]

[D-grade secret room’s friendly tip: The instance can be cleared by opening two password locks. Opening all password locks is a perfect clearance.]

[The clearance time is limited to 15 minutes. If this time is exceeded, you will fail. Please pay attention to the pendulum clock on the wall.]

The timing mode of the Hearts world was similar to the &#k2018;time bomb’. The red countdown number was always moving in the suspension box. The incomprehensible puzzle plus the countdown would inevitably give people psychological pressure.

The timing mode of this Diamonds world was a pendulum clock. This secret room was limited to 15 minutes and once the pendulum clock in the room moved from 19:00 to 19:15, the instance would end.

In the quiet and enclosed space, the ticking of the clock seemed to be multiplied and this would seriously interfere with people’s thinking.

Xiao Lou closed his eyes and forcibly ignored the clear bells in his ears, forcing himself to calm down.

He picked up the flashlight in the corner, raised it and carefully looked around the room.

Xiao Lou had played many secret room games. Some secret rooms were set up to have a stepping mechanism on the floor. If you accidentally stepped on a square, you were likely to fall into a pit. Therefore, after entering the secret room, he didn’t move around but stood in the middle of the secret room. He first figured out the locations of the mechanisms he needed to crack. Once he confirmed that there were no problems under his feet and above his head, he stepped forward to look at the walls.

There were many characters drawn on the four walls and a large hole dug under the walls. There was a wooden box inside and a lock on the box. The combination lock had four gears that could be unlocked by turning the gear to the correct number. At this point, all the locks and gears were in the initial state of 0000.

There were four password locks. Since only two was required to clear the instance, they could pick the ones they were good at. The D-grade secret rooms were really friendly to novices.

However, Xiao Lou wanted a perfect clearance.

It was only by getting a perfect clearance that he could draw a card and possibly get a S-grade card. In addition, obtaining more cards wouldn’t hurt.

Xiao Lou gazed at the wall in front of him.

Under the light of the flashlight, a nine numbered square appeared in the middle of the wall.

X/9/2

3/X/7

X/X/6

In a mathematical reasoning problem, a 3×3 disk was called a ‘palace’ and an advanced logical reasoning problem with nine palaces was called ‘Sudoku’. This was a frequently tested topic in professional quiz competitions.

Sudoku was a 9×9 disk with 81 squares. The challenger needed to infer the numbers on the remaining spaces according to the known numbers, satisfying every horizontal row, vertical row and every 3×3 single palace. They had to all contain numbers 1-9 and not repeat.

At this time, Xiao Lou was facing a 3×3 single palace disk.

He even did 9×9 Sudoku problems so forget the 3×3 single palace question. It wasn’t difficult for him at all.

In this palace, the four vacant Xs were the password.

The numbers to fill in the nine squares were 1-9. The numbers that appeared so far were 9, 2, 3, 7 and 6. According to the most basic ‘no repeating a number in a single palace’ rule, the missing numbers were 1, 4, 5 and 8.

How were these four numbers arranged as the password?

First, look at the known numbers. The third column of numbers was complete. 2+7+6 = 15. He could infer that the rule of the nine squares was for the horizontal and vertical columns to add up to 15. Then the first line was a 4, the second line was a 5 and the third line was an 8 and 1 respectively. This satisfied the rule of ‘horizontal and vertical columns = 15.’

The password was 4581.

Xiao Lou walked in front of the box and turned the password lock from 0000 to 4581.

There was a creaking sound and the box in front of him opened. He was surprised to find that there was a card inside the box.

[Special Effects Card: Nine Palaces Grid]

Rarity: C

Description: After completing the nine square palace reasoning problem of the 2 of Diamonds secret room, it can be obtained from the treasure chest.

Note: Throw the special effect card Nine Palaces Grid to the designated position and immediately form a 3m x 3m nine-square grid surface, locking up all targets within the nine square grid and making them unable to move for 9 seconds.

Number of times available: 9/9.

Xiao Lou’s eyes lit up!

The Hearts secret room was a unified settlement reward in the personal space after the instance was cleared. In the Diamonds secret room, there was a reward treasure chest waiting for every puzzle solved. It was like playing a stand-alone game and going through a maze, getting a treasure chest every time an area was unlocked.

Nine Palaces Grid was a special effects card. It might only be a C-grade rarity but it was a large-range skill that locked all targets in a 3×3 square. In a key moment, he could let the enemy stay in place for nine seconds and quickly escape.

This card combined with Tao Yuanming’s Remember Peach Blossom Spring meant that escaping wasn’t a problem.

The harvest of the special effects card was an unexpected surprise. Xiao Lou’s spirit was raised and he immediately walked to the left wall to continue the puzzle.

The mathematics problem on this wall was slightly more complicated than the nine square grid.

He saw four lines on the wall:

4894=1236

9795=1645

7743=1412

8376=??

Xiao Lou only looked at the question once before quickly answering.

Many people heard ‘numerical puzzle’ and subconsciously felt that their mathematics wasn’t good enough. In fact, numerical puzzles weren’t about a mathematical computing ability but logical reasoning ability. The key was to find the rule between the numbers.

In order to solve this question, careful observation was needed.

Xiao Lou only played secret room games and had a lot of experience with numerical reasoning.

The trick to numerical reasoning was to ignore the size of the number itself and look at each number separately. For example, the hint of this question was 4894=1236. It was easy to find that once you looked closely. 4+8=12, 9×4=36. The simple addition and multiplication of numbers coincided with 12 and 36.

The same was true for 9795=1645. 9+7=16, 9×5=45.

In other words, the first two numbers were added together to get the first two results. The last two numbers were multiplied to get the last two results. The three hints followed the same rule, proving that the solution was correct.

The final reasoning result of the last 8376 was obvious. 8+3=11, 7×6=42. The answer was 1142.

1142 was the password.

Xiao Lou went to the treasure chest, quickly changing the password lock to 1142.

Sure enough, there was a click and the box opened successfully in front of him.

There was another card in the treasure chest.

[Special Effects Card: Mathematical Equation]

Rarity: B

Description: After completing the equation-based reasoning problem of the 2 of Diamonds secret room, it can be obtained from the treasure chest.

Note: The effect of this card is very special. You can throw the mathematical equation at any specified target so that the target receives the same damage you suffered. Simply put, you drag them to share your fate when dying and it isn’t a loss :).

Number of times available: 2/2.

Xiao Lou, “...”

Why was a smiley face drawn at the end?

Was it necessary to drag someone else to death? The style of this Card World should improve!

Forcing the other person to receive the same damage as him meant sharing an end with others? Xiao Lou’s mouth twitched and he put the card in his card pack.

The rarity of the Mathematical Equation card was B, indicating that the number of challengers who solved this problem was relatively rare.

For this type of logical reasoning problem, it was very simple after finding the rule. If the rule wasn’t found then it couldn’t be solved. It was really hard for those who hadn’t played secret room games or touched numerical reasoning. It was estimated that they would be confused over this question.

Fortunately, the D-grade chamber could selectively open mechanisms. There were two choices out of four, the probability of finding a question to answer was quite large.

A prompt popped up on the suspension box. [Two mechanisms have been opened and the instance clearance condition has been reached. Do you want to leave the 2 of Diamonds secret room? Yes/No.]

Xiao Lou didn’t hesitate to choose No.

He turned t the next wall, shining the light on it and continuing to crack the next mechanism.

A perfect clearance was his pursuit!

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