Pocket Games
Sums
A grid of numbers, a target beside every row and column, and the job of deleting the ones you do not want. It looks like a game about addition and plays like the opposite: what matters is deciding what to take away.
The rules
The grid is full of numbers. Outside every row and every column there is a target. Your job is to delete some numbers so that the ones left in each row and each column add up to exactly the target beside it.
Every number belongs to a row and a column at the same time, and that is where the game comes from: deleting it to fix the row also changes the column’s total. The solution is unique, and you always get there by crossing between the two directions.
There are two tools: delete, for numbers that must go, and circle, for the ones you have decided to keep. Circling is not compulsory, but from the 5×5 up it is what holds your reasoning together: a circled number is a settled fact, and it shrinks the problem.
You have three lives: an incorrect move costs one and is corrected immediately, so you see what the right answer was. There is also one hint per level, which solves a cell of your choosing.
How to deduce
The zero target. If a row’s target is 0, every number in it goes. It is the gift the generator hands you now and then, and you should use it at once because it unlocks every column that row crosses.
The full target. If all the numbers in a row already add up to the target, you delete nothing: circle everything. Worth checking on every row at the start, it costs ten seconds.
The excess. Add up a row’s numbers and subtract the target: what remains is exactly how much you have to delete. If the excess is 4, you must delete numbers adding up to 4 — a 4, or a 3 and a 1. Often there is only one way to make that figure in that row, and the row closes itself.
The oversized number. If a row contains a number larger than its target, it goes without further thought: on its own it would already overshoot.
Crossing. This is the technique that solves the big grids. Once you have settled a cell via its row, look immediately at the column it belongs to: its excess has changed, and often there is now only one possible reading. Sums is played by constantly alternating directions, never by finishing one row at a time.
How the levels are built
You play through levels and the grid grows with you: the first three are 3×3 and serve as a tutorial, then twenty-five 4×4 levels, fifty 5×5, fifty 6×6, a hundred 7×7, and from there the game never ends, with grids between 6×6 and 8×8.
One detail makes the game nastier than it looks: in the tutorial the numbers run from 1 to 9, but from the 4×4 up they sit between 1 and 6. Numbers closer together mean far more combinations producing the same total, which means more traps: an excess of 5 can be made in many ways, and picking one at random is the standard way to lose a life.
Every grid is generated so that it closes by deduction, with no guessing required. The level you reach is saved, and with a Google account you find it on your other device.
Common mistakes
- Finishing one row at a time. It does not work: the information comes from the crossings, and anyone working row by row gets stuck on the third.
- Not circling. Without the kept numbers, after ten moves you can no longer tell what you deduced from what you merely left alone.
- Trusting the excess without checking the columns. An excess that can be made two ways is not a deduction: it is a bet, and it costs a life.
Frequently asked questions
Are Sums and Sumplete the same game?
Yes. Sumplete appeared in 2023 and became popular for a curious reason: it was presented as a game invented by an artificial intelligence. The rules are the ones described here.
Do I need to be good at maths?
No: you add numbers from 1 to 6, never more than eight at a time. The difficulty is logical, not arithmetical.
Can it always be solved without guessing?
Yes. Grids are generated by requiring that a chain of deductions exists that closes them, and the minimum length of that chain grows with the size of the grid.
What happens if I run out of lives?
The level restarts. Your overall progress is not lost: you resume from the same level, not from the beginning.
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