ARITH · PLAYER GUIDE
Your first round of arith
In arith, arithmetic comets descend toward Earth through a 3D night sky. Everyone visiting the game joins the same defense automatically. Type an answer and press Enter to blow up a matching comet. Your camera is your own; looking around does not move anyone else’s view.
Start with the controls
Open the game on a device with a keyboard. You join immediately without a login, name entry, or room code. Use the arrow keys to look up, down, left, and right. Type digits from 0 to 9. Backspace or Delete edits the answer; Enter fires it. The shared game keeps running while you read the help panel. Editing costs nothing, so correct a mistyped digit before submitting. Answers are nonnegative whole numbers from 0 to 99.
For a target reading 28 + 17, think 28 + 10 = 38, then 38 + 7 = 45. Type 45 and press Enter. If two comets have the same answer, one shot clears the matching comet closest to impact. It does not clear both.
Understand the ammunition counter
You start with 20 ammunition. Each shot costs one unit per digit typed, whether it hits or misses. A successful hit returns the digit count multiplied by the number of operators in that question.
| Target | Answer | Shot cost | Hit reward | Net change |
|---|---|---|---|---|
| 28 + 17 | 45 | 2 | 2 | 0 |
| 28 + 17 − 9 | 36 | 2 | 4 | +2 |
| No matching target | 45 | 2 | 0 | −2 |
Extra leading zeroes count as typed digits. Answer 7 with 7, rather than 007, to avoid an unnecessarily expensive miss. When your ammunition reaches zero, you cannot fire, but other visitors can keep defending. If all connected defenders run out of ammunition, the round ends. Press Enter to restart the shared defense.
Grow the shared civilization
CP means civilization points. Everyone shares the same CP and era, even though each visitor has an independent camera. Destroying a comet adds 10 CP once; a comet striking Earth removes 20 CP once. Points cannot go below zero. At zero, Earth is in Ancient time and play continues.
| CP range | Era |
|---|---|
| 0–99 | Ancient |
| 100–249 | Classical |
| 250–499 | Medieval |
| 500–999 | Industrial |
| 1,000–1,999 | Modern |
| 2,000–3,999 | Space Age |
| 4,000+ | Interplanetary |
For example, at 90 CP, one successful defense raises Earth to 100 CP and Classical. If a comet then hits Earth, the score falls to 80 CP and Ancient. The HUD shows both the current era and points needed for the next. These are game milestones rather than a historical timeline.
Defend together, look independently
The visitor count shows connected game sessions. Arrow keys affect only your own camera. A comet destroyed by another visitor disappears from your sky too. If two people answer the same comet at once, the server resolves one destruction and one CP reward; a later answer can miss if its target has already gone.
Keep scanning the sky
Comets appear continuously at random intervals from every direction. Each has its own speed. Look around with the arrow keys and use the radar to spot incoming comets behind you. Questions are smaller when far away and grow as they approach Earth. An empty field means a quiet moment before another comet appears.
A useful first-round routine
Find the comet closest to impact, calculate its answer, check your typed digits, then fire. Keep checking all directions as new comets arrive. After a missed shot, work through the expression slowly before firing again. Harder questions generally fall more slowly, but a comet already close to impact remains urgent. The sky radar shows comet directions relative to your view: the top is straight ahead, and the bottom is behind you.