Chapter 9
Chapter 9
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Translator: Ace
Chapter: 9
Chapter Title: Arithmomania
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Ding-dong-deng—
Class was over.
Seo-ha packed his textbooks and stationery into his bag. His head throbbed, and a feverish heat was rising—his condition wasn't great.
'I need to solve it quickly...'
The problem he'd been wrestling with since last night lingered in his mind. It was a variant of the Goldbach conjecture. A new approach had occurred to him, but he still hadn't completed it.
Seo-ha did some mental calculations on his time.
One day had 1,440 minutes. He'd used 521 so far. Subtracting sleep time (his family had a fixed lights-out)—480 minutes—and that left a pure usable window of 289 minutes.
'That's plenty. Almost five hours.'
Seo-ha hurried out of the classroom.
The key was not wasting time.
He exited the school gate precisely at 3:19:58. Twelve seconds to the crosswalk. Arrival at 3:21:08.
The light was due to change at 3:21:10.
Seo-ha had known this pattern for three years now. He'd memorized it naturally from commuting at the same time every day. The traffic light cycle was 120 seconds: green for 40, red for 80.
At lunchtime, there was a special pedestrian priority adjustment. He'd spent an entire day off once, timing the lights from dawn to dusk just to nail down the conditions. The effort had paid off—he had the perfect timing down.
One more step, and the light would change.
It should have...
But the light didn't change.
'What's going on? New rule added? Light malfunction?'
Yet everyone else waiting at the crosswalk looked perfectly calm, except for him.
'Where did I go wrong?'
His mind went blank. A pattern perfect for two years had broken. Seo-ha's breathing grew ragged. Sweat beaded on his skin. He started obsessively checking his watch.
Eleven seconds later, the light changed.
From 8 a.m., how many cycles had passed? From 8:00 to 3:21:21—that was 7 hours, 21 minutes, 21 seconds. In seconds: 26,481.
Divide by the cycle...
His steps slowed.
220.675
A decimal.
'0.675.'
27/40. Coprime. No further reduction.
'This is weird. No way a messy fraction like this shows up.'
Something was off. This couldn't happen. Amid the confusion, his body swayed.
"Huh?"
Seo-ha's body jerked to a halt.
Someone had grabbed his bag from behind and yanked him back.
"Beeeeeeep—"
A blaring horn erupted as a truck barreled past right in front of him.
That was close. He'd nearly died.
He turned to offer thanks...
"Seo-ha, are you okay?"
His mother's worried face. She'd run here—sweat beaded on her forehead. Seo-eun looked anxious too, on the verge of tears.
"Mom?"
The fever in his head cooled instantly.
'What the hell was I doing?'
"Why are you here...?"
Seo-ha blankly looked around.
He'd been at the school crosswalk—or so he thought. But this was the main road near home. He had no memory of getting here.
"We were coming back from shopping with Seo-eun! I spotted you, but you didn't answer when I called..."
That wasn't the whole story. Even from afar, Mi-young had seen her son's face drained white. Worried he might be sick, she'd scooped him up and sprinted.
"Oppa, hug!"
Seo-eun, now out of Mom's arms, reached for Seo-ha with both hands. He scooped her up lightly.
The familiar weight, the cozy scent.
Seo-eun wrapped her arms around her brother's neck.
Seo-ha's heart began to settle. The numbers swirling in his head faded, and the relentless calculations stopped tormenting him.
"Oppa, you okay? Your face is pale."
Seo-eun touched his cheek with her small hand.
"Of course I'm fine. Just a bit tired today."
He didn't want to worry the family, so Seo-ha forced a smile.
"Let's head home and rest. Mom'll make something tasty."
On the way, a cool breeze blew.
Splash, splash.
The stream gurgled in the ditch. Nearby, wildflowers shyly poked their heads out.
"Oppa, what's that flower called?"
"Daisy and hydrangea."
At five years old, everything in the world was a mystery to her.
Seo-eun peppered him with questions nonstop, but Seo-ha—who had the encyclopedia memorized—answered without missing a beat.
'Ah, peace. Just like our family always is.'
For the first time, his heart felt truly free.
Saturday morning at 10 a.m., Seo-ha boarded the No. 705 bus toward central Daejeon.
Gazing at the scenery flashing by outside, he reflected on the incident a few days back.
The memory blank. The near miss with the truck at the crosswalk.
And the trigger: the collapse of the traffic light pattern.
'I really could've died.'
Seo-ha had no intention of downplaying it. The anxiety came from suspecting something seriously wrong with him. More precisely, he couldn't bear the thought of his family grieving because of it.
'Time to uncover the cause.'
Analyze the phenomenon from the given conditions, hypothesize, and prove. Seo-ha decided to approach his issue with the logical thinking of a mathematician.
The bus reached downtown and disgorged its passengers. Following his prior research, Seo-ha headed straight for the largest bookstore in the country.
Inside, people lounged freely, flipping through books. Past essays, novels, workbooks—Seo-ha's steps faltered.
Shelves crammed with medical texts.
Modern Psychiatry, Introduction to Clinical Psychology, Neuropsychiatry, Adolescent Mental Health...
He scanned titles slowly until he found the one he wanted.
Understanding and Treating Obsessive-Compulsive Disorder
Flip, flip.
Obsessions, compulsions, various symptoms—but nothing matched his case exactly.
Flip, flip.
His rapid page-turning stopped. Seo-ha's hand trembled.
Arithmomania and mathematical thinking disorders.
Arithmomania is characterized by obsessive fixation on numbers and calculations. Patients perform endless mental arithmetic, assign meaning to specific numbers, and fixate excessively on mathematical patterns.
Main symptoms:
• Compulsive calculation of time, distance, quantities, etc.
• Excessive obsession with specific numbers or patterns.
• Uncontrollable urge to solve math problems.
• Extreme anxiety when calculations err.
• Severe impairment of daily functioning.
He slotted himself into each one.
The Goldbach variant that haunted him all night.
Years studying traffic light patterns—was that normal? Panicking when they broke?
Dividing his day into minutes and seconds—was that ordinary?
'When did these symptoms start?'
Seo-ha settled into a quiet corner chair and dug for more info.
"This guy's bad."
Kurt Gödel.
The 20th century's greatest logician. Revolutionized math with the incompleteness theorems, but in his later years, suffered severe obsessions and paranoia. Believed food was poisoned, ate only what his wife prepared. When she was hospitalized for six months, he starved himself to death.
"Tsk tsk."
'Way worse than me. No way a human just...'
But the next paragraph shattered his relief.
'Gödel's early symptoms were subtle. In his twenties, they were dismissed as mere fixation on mathematical precision. But untreated obsessions...
'Ah... damn it.'
'No, I'm different. I've already recognized the problem.'
Seo-ha checked other mathematicians.
Georg Cantor. Founder of set theory. In 1904, when his work was refuted at a conference, his obsessions escalated into bipolar disorder. Ended up institutionalized.
Isaac Newton. Suffered bipolar his whole life. Washed his hands dozens of times a day, had hallucinations.
Leonhard Euler. Teacher to all mathematicians. Went blind after cataract surgery in 1771. Yet he couldn't stop his compulsive calculations, obsessing over Uranus's orbit until death. At his funeral, his close friend Condorcet remarked: 'Death alone stopped Euler's calculations.'
Patients everywhere. Many great mathematicians had disorders, great or small.
Seo-ha moved to the diagnosis and treatment section for details.
"Ha ha!"
Coming to the bookstore was the right call.
Treatment wasn't as hard as he'd feared. Over 90% cure rate, better with early diagnosis.
'Gödel and Cantor's eras didn't even recognize it as an illness.'
He was different from them. The hopeful stats lightened his heart.
'Long live modern medicine!'
On the walk home, Seo-ha deliberately didn't time himself. Normally he'd clock the arrival precisely, but today? It didn't matter.
'Just wait if I have to. No big deal.'
He felt enlightened. When the light changed, he crossed naturally. No struggle, no pain.
'I can control this.'
Many great mathematicians had been trapped in numbers' prison forever. Seo-ha vowed he never would be.
He reached home but didn't check the time. Just opened the door.
"Mom!"
What did it matter how long it took? Normally he'd habitually note bus arrival and home arrival to calculate pace, but that was irrelevant now.
"I'm home!"
"Welcome back! Time to eat!"
It was dinnertime. Seo-ha quickly washed his hands and feet, helped set the table.
"Our Seo-ha always sets the utensils so neatly, right?"
"Yeah, yeah! He's done it since he was little."
The parents' praise warmed him. Seo-ha stared at the utensils he'd placed. The ends aligned perfectly with the square table's edge. A perfect right angle.
Unease flooded in.
"Here, have some sausage."
Taking the plate, he unconsciously used the tongs to remove one.
"What's wrong? Don't like sausage?"
Cheol-ho's question left Seo-ha speechless.
"Oh, honey! Seo-ha always puts exactly seven on his plate. Probably 'cause Seo-eun doesn't eat well."
No. That wasn't it. He just hated the number eight.
Was that all? Why insist on seven?
7 was a Mersenne prime (23-1). Also a safe prime, since (7-1)/2=3 is prime. The regular heptagon was the first regular polygon impossible to construct with straightedge and compass alone.
Seo-ha disliked perfect numbers like 6 (1+2+3=6) or cubes like 8 (2³=8) that expressed so neatly. 7 was just 7—no clean combos.
"Aaaah!"
Despair hit Seo-ha.
"What's wrong?"
Mi-young asked, seeing him clutch his hair.
"N-nothing. Just remembered I forgot homework."
He wolfed down dinner and retreated to his room. Leaning against the closed door, he let out a deep sigh.
'Totally screwed. Different my ass...'
A strange thought flickered. Unconsciously, he opened the closet.
Plaid clothes filled it.
'No... way.'
He grabbed a ruler from the drawer, held it to the patterns.
1 : 1.618
The golden ratio. Every outfit he'd ever liked.
His number obsessions, formed since early childhood, ran deeper than he'd imagined.
"Aaaargh! 90% cure rate! It was supposed to be easy!"
He dove under the covers, screaming into the pillow.
'Am I the remaining 10%?'
The good mood had blinded him to the positives—but mathematically, that 10% was no small number.