Sky Curtain: With a vermilion mirror, Jing travels through the modern world, shaking all dynasties.

"Is it really that miraculous?" Zhu Jingjing frowned slightly, her face full of disbelief.

The old scholar who taught her mathematics in the Daming Palace could manipulate the abacus with lightning speed, but when faced with complicated formulas, it would take him quite a while to figure them out!

"You don't believe me? Then I'll show you!" To give her a more intuitive understanding, Jiang Chuan didn't just use his phone to brush her off; instead, he pulled out an old calculator from a drawer.

After teaching her the basic button layout, I shoved the little gadget into her hand, saying, "Try it out for yourself!"

Zhu Jingjing tentatively pressed a few numbers, and with a final soft click, the answer instantly appeared on the screen.

"This is too fast! It got a result almost as soon as I finished typing. Could it be that there's a 'Zu Chongzhi' living inside this little gadget?"

The Imperial Observatory of the Tang Dynasty.

"The ecliptic revolves with the heavens, and the vessel aligns with the heavens; only then can the true nature be revealed."

Li Chunfeng stood with his hands behind his back in front of the armillary sphere, his fingertips lightly touching the inscription, lost in thought.

Suddenly, a dull, heavy rustling sound of armor plates rubbing together came from afar, shattering the tranquility of the Imperial Observatory.

"Who dares to make a scene in the Imperial Observatory?" Li Chunfeng frowned slightly and coldly ordered his men, "Men, drive that noise away."

Before the words were finished, a burly figure burst in.

The newcomer was clad in heavy black iron armor, a true elite of the Hundred Cavalry Division!

Ignoring everyone else, he walked straight to Li Chunfeng, clasped his hands in greeting, and said, "Lord Li! His Majesty has decreed that I be summoned immediately, without delay!"

Li Chunfeng's heart skipped a beat, and he thought to himself, "To send a hundred cavalrymen here must mean that something has happened to the state."

He immediately rushed out of the Imperial Observatory with a hundred riders, and saw a fine horse with its head held high outside the gate.

"Lord Li, mount your horse! We must proceed to Taiji Palace immediately!"

modern.

After entering the last complex equation, Zhu Jingjing looked at the answer that instantly appeared on the screen, still disbelieving: "Is this thing even accurate? Who knows if it's just random guessing!"

She stretched out her hand to Jiang Chuan, her tone spoiled and demanding, "Get me an abacus, I want to verify it myself!"

"An abacus?" Jiang Chuan stroked his chin and started pacing around the room. "I need to think about this! I think I actually bought one before, but I don't know where I put it!"

The Great Tang Dynasty, Taiji Palace.

Li Shimin, holding the baby rhinoceros in his arms, sat upright on the dragon throne.

Suddenly, he heard the sound of horses' hooves outside the palace, and he immediately got up.

"Your Majesty, what brings you to my court in such urgent order?" Li Chunfeng entered the hall, his breathing slightly disordered and not yet calm.

Li Shimin did not rebuke him, but simply pointed to the sky: "My dear minister, observe the heavens and see if the result of that calculation for me is absolutely correct?"

In the sky, Jiang Chuan casually recited a complicated equation, while Zhu Jingjing's fingertips flew across the "calculator," quickly pressing the keys to get the result, which she then checked with an abacus.

Li Chunfeng took the abacus presented by the eunuch, his ten fingers flew across the paper, the beads jingling crisply, and in just a few breaths he had obtained the answer.

"Your Majesty, I have calculated it!" He glanced at the strange symbols on the calculator, hesitated for a moment, and said, "The result of the calculation should be ninety-two. However, I do not recognize the symbols and do not know if they match the result obtained by the instrument."

Li Shimin nodded silently, waiting for Zhu Jingjing to provide an answer.

"It really is ninety-two, exactly the same answer as the calculator!" Zhu Jingjing exclaimed in surprise as she compared the results from the two items.

Upon hearing this, Li Chunfeng was shocked, as if struck by lightning!

Before the emperor, he held his breath and concentrated, his fingers moving the abacus beads like rain. Even with all his strength, it took him several breaths to get the answer!

And that wondrous artifact of later generations, with a mere touch of the fingertip, produced the result with perfect accuracy in the blink of an eye.

Such incredible speed could not have made him tremble with fear and tremble with terror!

"Perhaps it's a coincidence, let's try another one!" Zhu Jingjing was still unconvinced in the sky.

"Try a hundred more times and it will be the same!" Jiang Chuan said confidently, casually reciting an even more complicated formula.

"You're right again!" Li Chunfeng exclaimed in astonishment, his eyes wide. "This thing is truly a divine and unfathomable wonder! Even if Liu Hui were to be resurrected, or Zu Chong were to be reincarnated, and they joined forces with me, they would still be far from achieving this!"

Li Shimin slowly sat down, gazing intently at the sky with profound eyes.

After a long silence, he sighed, "The artifacts of later generations are all incredibly profound and exquisitely crafted; our Great Tang Dynasty is far inferior!"

The Great Ming Dynasty, Fengtian Hall.

"Chongba, what do you think of this?" Empress Ma asked softly, her gaze fixed on the sky.

Zhu Yuanzhang pondered for a long time before slowly speaking, "If we obtain this item, the Ministry of Revenue will be able to audit accounts much more efficiently and quickly in the future."

"If it can be widely promoted among the people, it will also facilitate business dealings! Moreover, compared with the abacus, the calculator is less prone to errors, which will greatly reduce disputes in the business world!" he added.

Empress Ma nodded slightly, a hint of regret flashing across her brow. "It's a pity that this object is so ingenious and its principles are difficult to understand. Even with the strength of our Great Ming Dynasty, we have no way of even beginning to imitate it!"

modern.

"How about that? Are you convinced now?" Jiang Chuan walked up to Zhu Jingjing and gently ruffled her hair.

"With this calculator, the abacus is truly useless. No wonder it was phased out!" Zhu Jingjing pouted, looking dejected. If she had known about this amazing tool, she wouldn't have bothered to learn how to calculate with an abacus!

"Jingjing, these are all my textbooks from when I was in school. I found them while looking for my abacus." Jiang Chuan picked up a bundle of books and gently placed them on the table. "Take these and look through them first. I'll buy you a brand new set online later."

"Jingjing, these are all my textbooks from when I was in school. I found them while looking for my abacus." Jiang Chuan picked up a bundle of books and gently placed them on the table. "Take these and look through them first. I'll buy you a brand new set online later."

Upon hearing this, the little princess curiously leaned forward and carefully began to flip through the pages.

"Brother, you guys are actually studying astronomy!" she exclaimed in surprise, picking up a book titled "Astronomy Activities." "I remember Father Emperor was a strict ruler who forbade the private study of astronomy!"

"This is an elective course, extracurricular reading, and not mandatory." Jiang Chuan took the textbook, casually flipping through a few pages. "As for your father's strict prohibition against private astronomical studies, I guess it was to consolidate imperial power—a kind of imperial tactic!"

Zhu Jingjing tilted her head, her face full of confusion: "Brother, I don't see any connection between astronomy and imperial power."

Jiang Chuan closed his textbook and sat down opposite her. "Then let me ask you, do you know what peasant uprisings in ancient times usually involved?"

The word "rebellion" made the little princess frown slightly. As royalty, any so-called rebellion was considered treason and a heinous act!

"How would I know? I've never rebelled..." She pondered for a long time before slowly saying, "They must be preparing food and weapons! After all, it's a rebellion; without food and weapons, it won't be easily suppressed!"

"Weapons and supplies are indeed important, but that's not what I'm referring to." Jiang Chuan shook his head slightly, pointing to the sky outside the window. "Then do you know why emperors throughout history have all claimed to be ordained by Heaven?"