Number puzzle — hit the target sum
A number puzzle is a game whose moves are arithmetic rather than shape-fitting. Neural Grid is a free browser version: drag a path through connected blocks so their values add up to exactly the target sum shown above the grid, while new rows keep rising from the bottom.
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What counts as a number puzzle?
Broadly, any game where the legal move is defined by arithmetic instead of by geometry. Sudoku is a number puzzle where the constraint is uniqueness. 2048 is one where the rule is merging equals. Kakuro is a crossword whose clues are sums. What they share is that the numbers are not scoring — they are the rules.
That distinction matters for what the game trains. In a shape puzzle the hard part is seeing where something fits; in a number puzzle the hard part is holding several partial sums in your head while you evaluate a fourth. The bottleneck is working memory doing arithmetic under time pressure, which is a noticeably different fatigue from spatial planning.
How does the target sum mechanic work?
Neural Grid shows a target number above a grid of numbered blocks. You press a block and drag through its connected neighbours, building a chain; release when the chain's values add up to exactly the target and those blocks clear. Too high or too low and nothing happens, so partial credit does not exist.
The pressure comes from the other direction: new rows push up from the bottom while you are thinking, and the run ends if the grid overflows the top. This makes it a rare puzzle where deliberation itself is costly — a perfect long chain you found too slowly can lose you the game that a merely adequate short chain would have won. Bombs exist for exactly that moment, clearing a stuck cluster and buying back space.
- Scan for two-block and three-block solutions first; they are fast and usually enough
- Clear from the bottom rows when you can — those are the ones about to become a problem
- Save bombs for a genuinely stuck board, not for a chain you cannot be bothered to find
- When the grid is high, take the fast small chain over the perfect long one
Where can I play a free number puzzle online?
Neural Grid is free in the browser, needs no download and no account, and is the hardest of the nine games on this site by some distance. It works with a mouse drag on desktop and a finger drag on touch.
If the arithmetic is not the part you enjoy, Cube Clear runs the same planning-under-constraint idea with shapes instead of sums, and with no timer at all — you place three pieces per turn on an 8x8 grid and clear full rows and columns. Both save your best score in your own browser.
Frequently asked questions
How do you play a target sum number puzzle?
Drag a path through connected number blocks so their values add up to exactly the target sum shown above the grid, then release to clear them. A chain that is too high or too low does nothing. New rows rise from the bottom while you think, and the run ends if the grid overflows.
Is there a free number puzzle game with no download?
Yes. Neural Grid on PlayNeon is a free browser number puzzle with no download, no installation and no account. It works with a mouse drag on desktop and a finger drag on phones and tablets.
What skill does a number puzzle train?
Problem solving and decision making under pressure. The specific load is holding several partial sums in working memory while evaluating another candidate chain — a different kind of effort from the spatial planning a shape puzzle demands.
What are bombs for in Neural Grid?
A bomb clears a stuck cluster of blocks and buys back board space. They are limited, so they are worth saving for a board that genuinely has no good chain rather than spending on one you have not looked hard enough for.