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Arithmetic
Long addition
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Long addition
Problem settings
Notation helper
Carry Scratchpad
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Type plain math or LaTeX-ish notation. Carry formats it as you write.
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Scratchpad editor
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Recent
Uses browser crypto randomness when available. Decimal output is rounded to the selected places.
Function grapher
Carry Grapher
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Prime Factors
GCD
Dated puzzles
Explorations
Games
Games
Easy is the default. Larger boards and harder puzzles add more open squares.
Mod Clock asks where repeated counting lands after wrapping around.
Choose every prime that divides the number.
Find the greatest whole number that divides both values.
Pick the rule that explains why the divisibility claim works.
Choose every number with the same remainder.
Tap nodes to trace a route from the green start to the flagged finish. You can only step along an edge. Find the route that uses the fewest edges.
Tap a node to cycle its assignment. Give every node one assignment without matching connected nodes. Conflicts become thick dashed edges.