Number Metro

Your train carries a number. Each stretch of track does a calculation, and riding it the other way does the inverse. A station only lets you stop if your number fits its rule. Plan a journey to the terminus on ten lines: negatives, inequalities, primes, powers, fractions, decimals, percentages, expressions and more.

Lines

Journeys

How to play
  • Click or tap a station next to the train (the glowing ones) to ride there. The arrow keys work too.
  • The label on a stretch of track is its calculation when you ride it in the direction of its arrow ➜. Riding the other way does the inverse: + 3 becomes − 3, × 2 becomes ÷ 2, □² becomes √□, +10% becomes ÷ 1.1. Track marked ▸▸ is one-way.
  • A station with a rule (such as < −5 or prime) only lets the train stop there if the number fits. The terminus has the number you need to finish with.
  • Undo (Z) takes back a ride; Restart (R) starts again (Undo brings it back). 💡 Hint (H) shows the next stop of a quickest journey, or tells you when you can't finish from here.
  • Three stars for the fewest rides. Your progress is saved on this device.

+ 3 ➜⬅ − 3 a calculation: the other way does the inverse one-way STOP IF n > 0 the train can only stop if its number n fits you can ride here now