Number pool (use each one once):
Pick an empty box, then choose a number from the pool
| Tap an empty box | Select where to place a number. |
| Tap a number | Place it from the pool. |
Number Pyramid stacks boxes so that every block holds the sum of the two directly beneath it. Some values are given and the rest come from a pool. Place them all correctly and the pyramid resolves.
It is addition working in two directions at once, which is what makes it a puzzle rather than a worksheet. Knowing a block and one of the two below it tells you the other by subtraction, so the pyramid unlocks from wherever you have the most information rather than from the bottom up.
Work from wherever two of three related boxes are known. If you know a block and one below it, subtraction gives you the other immediately. That is far faster than trying to fill the base row first.
Use the pool as a constraint. The available numbers tell you what is possible, so if a deduction gives you a value not in the pool, you have made a mistake somewhere earlier.
Check both directions. Every placement affects the block above and is affected by the two below, so verifying upward and downward as you go catches errors early.
Start with the smallest gaps. A row with only one empty box is fully determined, so filling those first cascades information into the rows around them.
Every block equals the sum of the two blocks directly below it.
No, each number in the pool is used exactly once.
Wherever two of three related boxes are already known, since subtraction then gives you the third.
Check that a deduced value actually exists in the pool. If it does not, an earlier placement is wrong.
No. Number Pyramid runs entirely inside this page, so it starts the moment the page opens. There is nothing to download, no plugin, and no account to create.