Sumday

About Sumday

Sumday is a free daily number game. Each day the puzzle is simply the date, written out as digits, such as 12/4/25 or 10/2/26. Your task is to turn those digits into a valid equation.

The one rule that shapes everything is that the digits must stay in their original left-to-right order. You cannot reorder them; you can only decide where numbers break and which operators go between them. On 12/4/25, for instance, the digits 1, 2, 4, 2, 5 can be grouped and signed into 1+24=25.

Because the puzzle is the calendar date, everyone plays the same one each day. The game shows a month calendar so you can step back to earlier dates and try those too, and it keeps simple stats on how you do.

It suits people who like quick mental arithmetic and number puzzles like Nerdle or Mathler, but prefer a single tidy challenge tied to the day rather than a guessing grid.

How to play Sumday

1. Read today's date shown as a row of digits.
2. Keep the digits in their left-to-right order, without rearranging them.
3. Decide where to split them into numbers (for example 2 and 4, or 24).
4. Place operators and an equals sign so both sides balance.
5. Submit your equation to solve the day's puzzle.

Tips

• Try grouping two single digits into one larger number to reach the value you need.
• Work out the right-hand side first, then build the left to match it.
• Remember the order is fixed, so plan splits before choosing operators.

Questions