Number Grid
About einstein number grids
Six-by-six grids with twelve interlocking equations and 14 to 22 blank cells. The thirty-six cells inside the grid hold each of −12 to −1 and 1 to 24 exactly once — no zero, and a third of the pool is negative. Negative intermediate values are possible everywhere, which means you need to track signs carefully as you work each equation out.
These grids are designed to resist casual guessing. You will need to chain deductions across several equations before placing a single value. If a row narrows a cell to two possibilities, check both against the column equation — usually only one works, and if both still stand, the pool breaks the tie: a number already placed somewhere else cannot be the answer. Einstein Number Grid puzzles take 15–30 minutes and are among the hardest arithmetic puzzles on this site.
For a different kind of extreme challenge, try einstein Kakuro or einstein KenKen.
How to play Number Grid
- Every row is an equation read left to right, and every column is one read top to bottom. Its answer sits at the end of the line — down the right-hand side, along the bottom.
- The arithmetic is the ordinary kind: × and ÷ are settled before + and −. So 2 + 3 × 4 is 14, not 20.
- Division always comes out exact. A value that would leave a fraction is the wrong value.
- The numbers you write INSIDE the grid come from a fixed pool, each used exactly once — the way a sudoku uses its digits. Easy and medium use 1 to 9, hard 1 to 16, expert 1 to 25, and einstein uses −12 to −1 and 1 to 24, with no zero.
- That pool is often the only thing that settles a cell. A blank whose row answer and column answer are both blank is pinned by nothing else — the arithmetic would take any number at all.
- The answers round the edge are NOT part of the pool. They are totals: whatever the arithmetic makes them, and they may repeat.
- From hard upward some of the round operation cells are blank too, so you work out the sign as well as the number.
- Every puzzle has one solution, reachable by logic alone.