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How to play Zero

Zero is a daily reverse countdown puzzle. Every day you get a starting number and a small set of math tools. Use every tool exactly once, in any order, to land on 0.

The rules

  • Every puzzle uses each tool exactly once.
  • Tools can be addition, subtraction, multiplication, or division.
  • You must land on 0 — no overshoot, no remainder.
  • Your timer starts on the first tap and stops the moment you hit 0.
  • Tapping undo adds a small penalty, so plan the order before you commit.

Zero's moods

Zero is the little character at the top of the puzzle. Watch the face — it's a hint about how the run is going.

  • Calm — the number is in range, you're on track.
  • Excited — you've shrunk the number quickly. Stay sharp.
  • Surprised — a multiply or add just made things bigger. Adjust the order.
  • Triumphant — you've landed on 0. Time stops.

Strategy

  1. Solve before you tap. Glance at the operators and work out a path mentally. The clock only starts on your first move.
  2. Multiplication and division first. They reshape the number the most. Use them while the value is still flexible.
  3. Save your biggest subtraction for last. If you can engineer the number into something the final subtract can erase, you win cleanly.
  4. Watch divisibility. A ÷3 only works on a multiple of 3. Sometimes a +N earlier is the unlock.
  5. Undo costs time. Plan two moves ahead instead of trying tools at random.

Daily play

A new puzzle drops every day. Signed-in players record times, compete on the leaderboards, and unlock the archive of past puzzles. Anonymous players get unlimited practice puzzles with no timer pressure.