On the first day, Mun Saeon looked up before doing anything else.
Moaddeul Academy was a tower. Wide hallways circled each floor, with stairs climbing between them. From down here, Saeon could see the lights on the upper floors. But not the top.
Saeon tapped the edge of a blank card. Nothing had started yet, but Saeon's feet already pointed toward the stairs.
“Saeon, Sodam, Dure. Class F.”
Teacher Gwak Doeun called them over. A navy-blue display appeared in front of Saeon. Its top-left corner had a little stair-shaped notch.
Floor 1 · Class F
Assignment Complete · Math Puzzle Gallery
The very bottom floor. Saeon looked up again. Those stairs started right here, too.
“So we go up.”
Gi Sodam studied the hallway to the side instead. Yun Dure held a honey-colored notebook and looked where the teacher was pointing. Saeon turned, too. Today's activity was over there.
A navy stone table stood in the Puzzle Gallery. It had eight corners and three small round lamps along its edge. Every lamp was dark.
“Here. The lights are off.”
Dure pointed to the nearest lamp. Saeon leaned in, but a voice came from upstairs.
“I cleared this one two different ways.”
It was Pyo Ichan from Class A, standing straight behind the railing. Ichan held up two fingers at chest height.
“See you at the move-up challenge.”
Saeon lifted one shoulder. There hadn't even been time to look at everything on the table. Still, a method would come along soon enough.
“Our turn, then.”
Blue-glowing spheres lay in the middle of the table. Three rows of four. Twelve altogether. The teacher called them energy cores. All the same size, all the same glow. Each smooth sphere sat apart from the others.
There were three empty silver trays with rounded edges. One for Saeon, one for Sodam, and one for Dure.
The teacher stepped back.
“Share them all out. The same amount for each of you.”
“I'll try first.”
Saeon's hand shot up. All twelve had to go onto the trays. Clearing the middle would be easy.
Saeon put five on the nearest tray. Four went onto Sodam's, and three onto Dure's. The last core left Saeon's hand. The middle of the table was empty.
Five, four, three. Added together, twelve.
“Twelve altogether. Done!”
Saeon lifted both hands away. But the lamps stayed dark. Saeon checked the middle again. No forgotten spheres. None in either hand, either.
Sodam adjusted one arm of the glasses.
“Hang on. There are two conditions.”
“I shared them all out.”
“None left over. And equal shares.”
Sodam pointed to the empty middle, then to each tray. Saeon replayed the teacher's words. After “share them all out,” there had been something else.
The same amount for each of you.
Five for Saeon. Four for Sodam. Three for Dure. Using every core wasn't the same as giving everyone an equal share.
Dure raised a hand.
“Not yet. Hear me out.”
Saeon's hand stopped on its way back to the table. This time, Saeon waited for Dure to finish.
A display with a stair-shaped corner appeared beside the table.
Surprise Quest
12 cores. Unequal shares.
How can you make it fair?
Reward: New Skill
A share was the number of cores one person got. Saeon looked from the nearest tray to Dure's. Moving some from here might work.
But Saeon didn't reach out yet.
From the five-core tray to the three-core tray. How many would make them equal?
Without touching a core, Saeon pointed between the two trays. One core moving across. Saeon pictured it: one fewer here, one more for Dure. Sodam's four stayed put.
Dure pointed to those same two spots.
“Here. Just move one.”
Saeon nodded.
“One from the bigger pile. Then we'll all have four.”
Saying it made the next move clear. No need to put more in the middle or fetch any new cores. Just move one of the cores already here.
“Okay. Let's change it.”
Saeon picked up one core and set it on Dure's tray. Then pulled back and counted again.
Four for Saeon. Four for Sodam. Four for Dure.
All three lamps came on together. Light spread along the silver rim. Saeon looked down at the hand that had moved just one core. Somehow, all three trays looked different now.
Sodam checked the middle. Dure looked across the trays. Saeon followed their eyes. An empty middle. Equal shares. Both conditions worked now.
“Wait. A little space opened in the table.”
Saeon bent closer. A shallow recess had opened in the outer edge. The solid rim had parted there.
Inside lay a tiny stair piece. Three steps rose from bottom to top, their corners rounded. No letters. No patterns. It looked like a little section cut from the stairs Saeon had just looked up at.
But the light didn't only go up.
Blue light flowed along the piece, then curled back down. Saeon started to reach for it but kept the hand outside the recess. The direction was clear without taking it out.
“The light comes back down,” Sodam said.
Saeon looked underneath the piece again. Stairs meant going up. This light seemed to know the way down, too.
“Maybe it connects to the top.”
Saeon pictured the tower overhead. The piece offered no answer. Light passed beneath it once more, and the recess slowly closed. Saeon's hand was still empty.
The three trays still held four cores each. After checking the mechanism that had opened, the teacher turned to Saeon.
“What did you change?”
Saeon pointed to the nearest tray and Dure's.
“I moved one from the tray with five. Now we all have four.”
This time, that wasn't the whole explanation. Saeon pointed to the middle, too.
“And we used all twelve.”
The teacher gave a small nod.
“Nice and clear.”
Saeon turned to Sodam.
“I almost stopped at the total.”
“The total and each share are different things.”
Sodam pointed across the three trays. Dure opened the notebook and ran a finger along the bottom of the page.
“Four each. None left.”
Twelve shared equally among three people meant four each. A short equation appeared beside the table.
12 ÷ 3 = 4
Saeon looked from the equation to the trays. Twelve cores had become four each for three people. Put those shares back together, and there would still be twelve.
Twelve at the start. Twelve now. What had changed was the number each person got. Saeon studied the trays a little longer than the equation.
A new display appeared.
Quest Clear
Equal shares · None left over
Saeon · Next Path: Condition Pin
New Skill: “Fair Shares” — Division
Condition Pin. Saeon remembered Sodam pointing to the empty middle, then the three trays. Next time, maybe Saeon could check both before starting. That hadn't happened yet.
Saeon looked up at the teacher.
“Teacher Gwak, can we do it another way?”
“Of course. Next time, all three of you explain.”
Saeon looked again at the trays of four. There had to be a way to share equally right from the start. Ichan had said two ways. Now that Saeon had found one, finding another sounded good.
A notice appeared by the stairs.
Next Move-Up Challenge
End of Term · One Gate in Each Area
Clear a gate to move upstairs
Same problem as Class A · Compete by the number of methods found
Condition: All three explain in their own words
Saeon glanced at Sodam and Dure. Being the first to raise a hand wouldn't finish that challenge. All three would have to explain what they had done.
Saeon called up to Ichan.
“I'll show you our second way at the challenge.”
Sodam lowered the hand from the glasses. Dure closed the notebook. Leaving the three lit lamps behind, they walked into the wide hall by the open stairway door. Today, they were still on the bottom floor.
Saeon stopped and looked up again. Before, all that mattered was the way up. Now Saeon remembered the light curling down around the little stair piece, too.
What was at the top?