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Sudoku
rows · columns · boxes
4×4
6×6
9×9
12×12
Fill the grid so every row, column and box contains each digit exactly once. Four grid sizes from beginner 4×4 to expert 12×12.
Easy → Devilish
4 grid sizes
Step-by-step solver
▶ Play Sudoku
➕
Calcudoku
cage arithmetic · deduce
4×4
6×6
7×7
8×8
9×9
Each cage must reach its target using the given operation. Try Operators Hidden mode — the hardest variant where you must deduce both the digits and the operation.
4 operator modes
Hidden ops
5 grid sizes
▶ Play Calcudoku
☠️
Killer Sudoku
cage sums · no operators
9×9
Standard Sudoku rules plus cage constraints — digits within each dotted cage must be unique and sum to the cage's target. No operations given.
Easy → Devilish
Unique cage digits
Solver included
▶ Play Killer Sudoku
🔗
Number Snake
connect the numbers · find the path
5×5
6×6
7×7
8×8
9×9
10×10
Fill in the missing numbers so that 1, 2, 3 … N form a connected chain. Each number must touch the next — sides and corners both count. Also includes Orthogonal where only sides count.
Easy → Devilish
Number Snake + Orthogonal
Step-by-step solver
▶ Play Number Snake
↔
Futoshiki
fill the grid · satisfy the arrows
4×4
5×5
6×6
7×7
Place numbers 1–N so every row and column holds each number once. The arrows between cells tell you which neighbour is bigger — the arrow always points from the larger to the smaller number.
Easy → Devilish
Pencil notes
Step-by-step solver
▶ Play Futoshiki
∑
Magic Sum
fill the grid · hit every total
3×3
3×4
4×4
3×5
4×5
Place every number from 1 to N exactly once in the grid. The blue totals at the edge of each row and column are your targets — every row and column has its own individual sum to hit.
Easy → Devilish
5 grid shapes
Step-by-step solver
▶ Play Magic Sum
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Magic Difference
subtract across · hit every target
3×34×45×56×6
Subtract each row and column from its anchor cell — the result must match the edge target. Enable negative targets for extra challenge.
Easy → DevilishNegative targets optional
▶ Play Magic Difference
×
Magic Product
multiply across · hit every target
3×34×45×56×6
Every row and column must multiply to the edge target. Think in factors — a completely different mental mode from addition puzzles.
Easy → DevilishFactorisation thinking
▶ Play Magic Product
÷
Magic Division
divide across · hit every target
3×34×45×56×6
Divide each row and column from its anchor cell sequentially. Enable decimal targets for harder puzzles where results aren't whole numbers.
Easy → DevilishDecimals optional
▶ Play Magic Division
±×
Magic Mixed
rows ≠ columns · 10 combos
3×34×45×5
Pick a different operation for rows and columns. Sum rows with product columns, difference rows with division columns — 10 combinations to explore.
10 op combosEasy → Devilish
▶ Play Magic Mixed
✦
Magic Path
connect numbers · 81 math rules
4×45×5up to 12×12
Find all numbers matching a rule — primes, multiples, Fibonacci, fractions, percentages and many more — then connect them in one continuous path. Drag horizontally, vertically or diagonally.
81 rules4 × 4 → 12 × 12Easy → DevilishWorks offline
▶ Play Magic Path
Σ
Kakuro
cross-sum puzzle · fill the runs
6×6
8×8
10×10
12×12
Fill white cells with digits 1–9 so each run of cells reaches its clue total. No digit may repeat within a single run. The cross-sum classic — harder than it looks.
Easy → Devilish
Pencil notes
Step-by-step solver
▶ Play Kakuro
◼
Hitori
shade · no adj · stay connected
5×59×9
Shade cells so no number appears twice unshaded in any row or column, no two shaded cells touch, and all unshaded cells remain connected.
Easy → ExpertSolver included
▶ Play Hitori
🌊
Nurikabe
islands · river · no 2×2
5×59×9
Divide the grid into white islands and a black river. Each island has one clue equal to its size. River must be connected with no 2×2 blocks.
Easy → ExpertSolver included
▶ Play Nurikabe
⬜
Pearl Path
closed loop · black & white pearls
5×512×12
Draw a single closed loop through every pearl. Turn at black pearls, go straight through white pearls with a compulsory adjacent turn.
Easy → ExpertSolver included
▶ Play Pearl Path
🏙️
Skyscrapers
towers · count what you can see
4×47×7
Every row and column holds each height once; edge clues count the towers visible from that side.
Easy → ExpertSolver included
▶ Play Skyscrapers
⚪
Binary Puzzle
0s & 1s · never three in a row
6×612×12
Zeros and ones, half and half in every line, no three in a row and no twin rows. Also called Takuzu.
Easy → ExpertSolver included
▶ Play Binary Puzzle
⭐
Star Battle
one per row, column & region · no touching
5×512×12
Place stars so every row, column and coloured region has the same number — and no two stars touch, even diagonally. The classic behind today’s daily region puzzles.
Easy → ExpertSolver included
▶ Play Star Battle
🟪
Rectangles
split the grid · each number is an area
5×515×15
Divide the grid into rectangles, one number in each, equal to its area. Every clue is a factor-pairs question — great maths practice.
Easy → ExpertSolver included
▶ Play Rectangles
🌉
Bridges
join the islands · bridges never cross
7×715×15
Connect the islands with single or double bridges so each has as many as its number, and every island joins up. Visual, calm and very satisfying.
Easy → ExpertSolver included
▶ Play Bridges
🖼️
Nonogram
shade from the clues · reveal the picture
5×525×25
Classic picture logic: shade blocks from the number clues to uncover a hidden image — over 300 pictures, colour puzzles and random patterns.
Easy → ExpertSolver included
▶ Play Nonogram
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Tents
a tent for every tree · never touching
6×615×15
Pitch one tent beside every tree so no two tents touch and every row and column has the right count. Friendly, calm and great for younger solvers.
Easy → ExpertSolver included
▶ Play Tents
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Light Up
light every square · bulbs never clash
5×514×14
Place bulbs so every square glows, no two bulbs see each other, and numbered walls touch the right number of bulbs. A lovely glowing puzzle.
Easy → ExpertSolver included
▶ Play Light Up
➕
Kakurasu
shade squares to make every total
4×49×9
Each shaded square counts its column number in its row and its row number in its column. Make every total add up — addition practice disguised as logic.
Easy → ExpertSolver included
▶ Play Kakurasu
➰
Slitherlink
draw one loop around the numbers
5×510×10
Join the dots into a single loop. Each number says how many of its square’s sides the loop uses — no crossings, no branches.
Easy → ExpertSolver included
▶ Play Slitherlink
🌌
Galaxies
split the sky into balanced galaxies
5×512×12
Each galaxy holds one dot and looks the same when spun half a turn around it. Paint the squares — auto-mirror helps — until every galaxy glows.
Easy → ExpertSolver included
▶ Play Galaxies
🌗
Sun & Moon
balance suns and moons with = and × signs
4×410×10
Equal suns and moons in every line, never three in a row — and = or × signs between squares. The signs twist on Binary.
Easy → ExpertSolver included
▶ Play Sun & Moon
🧩
Sudoku Variants
fifteen twists on classic sudoku
4×49×9
X, Windoku, Jigsaw, Kropki, XV, Anti-Knight, Anti-King, Non-Consecutive, Even–Odd, Thermo, Sandwich, Arrow, Little Killer, Consecutive and Whisper lines — with notes, hints and a step-by-step solver.
Easy → ExpertSolver included
▶ Play Sudoku Variants
〰️
Number Path
one path through every square, in order
5×58×8
Start on 1, pass every number in order and cover the whole grid in one stroke — with optional walls in the way.
Easy → ExpertSolver included
▶ Play Number Path
⭕
Sum Circles
place 1–9 so every circle adds up
3×34×4
Nine squares, four circles. Each circle is the total of the four numbers around it — plus colour totals and a 4×4 challenge.
Easy → ExpertSolver included
▶ Play Sum Circles
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Equation Square
place 1–9 so every sum works
3×3BODMAS
A 3×3 grid of numbers with + − × ÷ between them. Make every row and column equal its answer — a crossword made of sums.
Easy → ExpertSolver included
▶ Play Equation Square
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Number Chain
follow the steps in your head
4 – 10 stepsEasy – Expert
Double it, take 7, find a quarter… keep a running total in your head. Four levels from times tables to percentages and cubes.
Easy → ExpertSolver included
▶ Play Number Chain
🧱
Number Blocks
1 to n in every block, no touching
5×510×10
Fill each block with 1 up to its size. The same number never touches itself — even diagonally. Simple rules, satisfying logic.
Easy → ExpertSolver included
▶ Play Number Blocks
🔐
Letter Sums
each letter is a digit — crack the code
Word sumsCode sums
Classic word sums like SEND + MORE = MONEY, and code sums that hide a ten-letter word. Column-by-column hints show how.
Easy → ExpertSolver included
▶ Play Letter Sums
🎯
Make the Number
hit the target with + − × ÷
Kids6 numbers
Six numbers, one target. Combine them with + − × ÷ to make it exactly — or play the kids’ version with four small numbers.
Easy → ExpertSolver included
▶ Play Make the Number
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Number Regions
every region is the size of its number
5×58×8
Fill in numbers so each joined group of equal numbers is exactly that big. Drag to copy numbers and watch the regions click into place.
Easy → ExpertSolver included
▶ Play Number Regions
🌊
Ripple Rooms
fill the rooms, mind the ripples
5×510×10
Each room holds 1 to its size. Equal numbers in a row or column must be at least that far apart — big numbers make big ripples.
Easy → ExpertSolver included
▶ Play Ripple Rooms
👀
Sightlines
numbers count the squares they can see
5×510×10
Shade squares to block the views so each number sees exactly its count. No touching shaded squares, and whites stay joined.
Easy → ExpertSolver included
▶ Play Sightlines
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Fleet Finder
find the fleet from the counts
6×610×10
Use the row and column counts to locate every ship. Ships lie straight and never touch, even diagonally.
Easy → ExpertSolver included
▶ Play Fleet Finder
🖼️
Mosaic
numbers count the shaded squares around them
10×1020×20
Shade squares so each number matches the count in its 3×3 block — and watch a picture appear. Pictures or random patterns.
Easy → ExpertSolver included
▶ Play Mosaic
🁫
Domino Hunt
find every domino of the set
0–30–9
A full set of dominoes is hidden in a grid of numbers. Find where each lies — every domino appears exactly once.
Easy → ExpertSolver included
▶ Play Domino Hunt
🔺
Number Pyramid
each brick is the sum of the two below
3 rows7 rows
Fill in the missing bricks by adding, subtracting — or multiplying in the times version. From first steps to algebra.
Easy → ExpertSolver included
▶ Play Number Pyramid
✏️
Cross Numbers
a crossword where every answer is a number
4×46×6
Squares, primes, multiples, digit sums and links between answers — fill the grid so every maths clue fits.
Easy → ExpertSolver included
▶ Play Cross Numbers
🌡️
Thermometers
fill from the bulb to match the counts
5×510×10
Fill thermometers from the bulb with no gaps so every row and column count is right.
Easy → ExpertSolver included
▶ Play Thermometers
💧
Water Tanks
water lies flat — fill to match every count
5×510×10
Fill tanks with water that settles at the bottom and lies flat, so every row and column count is right.
Easy → ExpertSolver included
▶ Play Water Tanks
🧲
Magnets
place the + and − ends to match every count
5×68×8
Decide which plates are magnets and which way round. Like signs never touch; the counts give the + and − in each line.
Easy → ExpertSolver included
▶ Play Magnets
🔤
Edge Letters
each letter once — the edges show who comes first
4×47×7
Place each letter once per row and column; blanks fill the rest. Edge letters show the first letter seen from that side.
Easy → ExpertSolver included
▶ Play Edge Letters
🗺️
Four Colours
colour the map — neighbours never match
6×612×12
Use four colours so no neighbouring regions share one. Some regions start coloured; there is exactly one answer.
Easy → ExpertSolver included
▶ Play Four Colours
🪞
Mirror Maze
fish, birds and frogs — the mirrors tell
4×47×7
Use lines of sight that bounce off mirrors to find every creature. Birds show only directly, fish only in mirrors, frogs always.
Easy → ExpertSolver included
▶ Play Mirror Maze
💡
Light Switch
every press flips its neighbours
3×37×7
Switch all the lights off. Each press flips a square and its neighbours — a classic puzzle with a neat mod-2 solution.
Easy → ExpertSolver included
▶ Play Light Switch
🚂
Train Tracks
lay one line from A to B
6×610×10
Use the row and column counts and the pieces in place to lay a single railway from A to B. No loops.
Easy → ExpertSolver included
▶ Play Train Tracks
🔧
Pipe Link
turn the pieces into one network
4×48×8
Rotate pipe pieces until they all join up: no leaks, no loops, nothing pointing off the board.
Easy → ExpertSolver included
▶ Play Pipe Link
📏
Straights
no repeats — every compartment a straight
5×59×9
Fill the white squares so no number repeats and every run of white squares is a set of consecutive numbers.
Easy → ExpertSolver included
▶ Play Straights
🁢
Domino Shade
two in every region — all dominoes
5×58×8
Shade two squares per region so the shading forms dominoes that never touch side to side.
Easy → ExpertSolver included
▶ Play Domino Shade
🧩
Tetro Shade
one piece of four in every region
5×58×8
Shade an L, I, T or S in every region. Everything joins up, no 2×2 blocks, and matching shapes never touch.
Easy → ExpertSolver included
▶ Play Tetro Shade
🏠
Room Shade
shade the rooms, keep the white joined
5×510×10
Each numbered room has that many shaded. No touching, white stays joined, and no white line crosses two walls.
Easy → ExpertSolver included
▶ Play Room Shade
➿
Arrow Loop
one loop, arrows count the shading
5×510×10
Shade some squares and loop through all the rest. Arrows count shaded squares; shaded squares never touch.
Easy → ExpertSolver included
▶ Play Arrow Loop
🔢
Sliding Tiles
slide every tile home
3×34×4
The classic 8 and 15 tile puzzle, with numbers or pictures. Hints follow the shortest route home.
Easy → ExpertSolver included
▶ Play Sliding Tiles