How to play
- Goal
- Place 1 through the chart’s size once on the top edge and once down the left, matching every printed product.
- How it ends
- A chart is complete when both header edges and every printed product agree; there is no loss.
- Record
- Your first unassisted solve of each chart earns one fastest-time record; replays are practice.
- Choose a number, then tap a top or left header. Place 1 through the chart’s size once on each edge. Tap the same number again to erase it.
- Each printed interior number equals its row factor times its column factor. A number may appear on both edges, but never twice on the same edge. Blank interior cells impose no condition and need no entry.
- The worked picture shows an empty twelve clue, a valid three times four, and a rejected two times four. Undo and Redo correct placements; Restart clears headers while the original first clock continues.
Controls
| Choose factor; tap / click header | Place the selected number; repeat the same number to erase |
|---|---|
| Arrow keys; number keys | Follow the two header edges; set a factor |
| Enter; Delete / Backspace | Use selected factor; erase |
| Z / Y; Undo / Redo | Reverse or restore a factor placement |
| Restart | Clear headers after confirmation; keep the first clock |
| Escape | Close a dialog or return to the atlas |
| Gamepad | D-pad moves, A places, X erases, shoulders choose, Y undoes, B returns and Start opens Settings |
Tips for Factorism
- Start with a forced pair Only factor pairs within the chart’s number range are possible.
- Cross the clues Several products in one row or column share that header’s factor.
- Use each missing number An edge’s final empty header is forced even if its row or column has no clue.
Questions about this game
Can a row and column use the same number?
Yes. Each edge has its own complete set of numbers.
Do I fill empty interior cells?
No. Only the top and left headers are editable.
Can replay improve my first time?
No. Your first completed time remains saved; replay is untimed practice.
All charts are open. Progress saves in this browser; a reloaded attempt finishes locally on its original clock.
Watch how to play
About Factorism
Restore a brass counting table by placing a separate set of numbered factors along each edge. Their products must match the scattered clues inside.
All 160 original charts are open from the start. Each has one independently checked answer and a deduction path, across four shelves of compact four- and five-factor tables.
Your first completed time stays with each chart. An uninterrupted first solve on the game page can claim the named best; replay is untimed practice.
