Numbers in Stone

Choose a number system above. Each has its own surface: a stone, a clay tablet, a limestone slab, a marble stele or a Maya stela.
To read, look at the signs, add them up, and tap the card with the number.
To write, tap the signs under the surface to carve or press them in. Tap a sign you placed to take it back, then Check.
Babylonian and Maya numbers have places. Tap a place to choose where the next sign goes.
Eight rounds a game, easy to hard. Some use real numbers: years on title pages, lines from tablets, counts on monuments.
On a keyboard: 1 to 4 pick a card. Letters or number keys write signs, Backspace takes one back, Enter checks, and the arrow keys move between places.

Number help has every sign of the system you are playing.

The rules follow Cajori (1928), Smith (1925) and Morley (1915). Every sign is our own drawing after their pages.

A bug, a puzzle that felt unfair, an idea? Tell us: we read everything.

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