Brain training, mental math & focus

KenKen vs Kakuro

KenKen fills a square Latin-square grid using cages with all four operations (+ − × ÷); Kakuro fills a crossword of addition runs. The real differences explained — and which one to try first.

Puzzle strategy

Kakuro vs Crossword

Same grid, different language — Kakuro fills squares with digits that add to each clue sum; a crossword fills them with letters that spell words. The key differences explained and which to try first.

Puzzle strategy

Sumplete vs Killer Sudoku

Sumplete starts full and you delete numbers down to each row and column target. Killer Sudoku starts empty and you fill digits up, obeying placement rules and cage sums. Same arithmetic instinct, opposite direction.

Puzzle strategy

KenKen vs Killer Sudoku

Both puzzles use arithmetic cages — but KenKen allows cage repeats and runs four operations (+ − × ÷), while Killer Sudoku forbids repeats and uses addition only. Rules compared and which to try first.

Puzzle strategy

Binairo vs Sudoku (Binary Puzzle)

Both are logic grids — but Binairo uses only 0 and 1 with balance rules, while Sudoku places digits 1–9 across rows, columns, and boxes. Rules, difficulty, and which to try first.

Puzzle strategy

How to Solve Binairo (Binary Puzzle)

Fill a grid with only 0s and 1s: no three of the same in a row, each line balanced, every line unique. Avoid-Three pair and sandwich patterns unlock most moves — no guessing needed.

Puzzle strategy

How to Solve Hitori Puzzles

Shade duplicates so no number repeats in a row or column, shaded cells never touch, and all white cells stay connected. Pair and Sandwich patterns unlock the grid — no guessing needed.

Puzzle strategy

How to solve Suguru (Number Blocks Puzzle)

Fill each irregular region 1 to its size while no two equal numbers touch — even diagonally. Start small, sweep neighbors, and let the cascade do the rest.

Puzzle strategy

How to solve Futoshiki (Inequality Puzzle)

Fill the grid so every row and column holds each digit once — while obeying the greater-than and less-than signs. Extreme-value rule, chain logic, and Latin-square elimination explained.

Puzzle strategy

How to Estimate in Your Head

When a rough number beats exact — rounding, front-end, and compatible-number tricks for fast everyday mental estimates. Free game included.

Mental math

Mental math for seniors

A gentle, no-pressure way to keep your numbers sharp as you get older — how to practice comfortably, easy daily ways, and a free large-tile number game.

Seniors

Daily brain exercises for seniors

How to build a simple 10-minute daily puzzle routine that sticks — which puzzles work best for seniors, what to avoid, and free ones to start right now.

Seniors

Math puzzles for adults

The main types of math puzzles explained — arithmetic, Sudoku-style grids, cross-number, and sequences — plus free ones you can play right now. No app, no sign-up.

Brain teasers

Lateral thinking puzzles for adults

Lateral thinking puzzles for adults, with answers — plus how to solve them. Learn the strategies, try 10 situation puzzles, and play them with friends.

Brain teasers

Brain teasers for adults

Brain teasers for adults come in 5 types: lateral thinking, math, word puzzles, visual, and logic riddles. Find the one that fits your thinking style.

Brain teasers

Math word problems for adults

A four-step method for everyday math word problems, with five real-life worked examples and free in-browser practice.

Mental math

Math riddles for adults

Nine brain teasers with a hint before every answer — try each one first, then check the full solution. From movie tickets to a snail in a well.

Brain teasers

Free printable brain games for seniors

Large-print number puzzles and worksheets you can download and print at home — no sign-up. Includes a quick online version too.

Seniors

Number bonds for adults

The five make-ten pairs that speed up everyday mental math — plus a free game and printable worksheet to drill them.

Mental math

How to improve your mental math

The "make ten" trick and five simple strategies anyone can learn — plus a free number game to practice with.

Mental math

Brain games for seniors

Ten free, no-download games to keep your mind active — and the honest answer on whether they really work.

Seniors

How to get better at Sudoku

Stuck on the hard ones? Learn scanning, pencil marks, naked pairs, and hidden singles — in the right order.

Puzzle strategy

How to play Killer Sudoku

Cages, the 45 rule, and how to solve it like normal Sudoku — a step-by-step guide for adults.

Puzzle strategy

Mental multiplication tricks

Six tricks — ×11, ×9, ×5, squaring, and doubling — that make multiplying in your head click for adults.

Mental math

Brain games like Sudoku

Thirteen free number and logic puzzles in the same family as Sudoku — plus one you can play right now.

Puzzle strategy

How to solve Kakuro

Magic number combinations and cross-referencing explained — a beginner's guide to cracking the Kakuro grid.

Puzzle strategy

How to solve Nonograms

The overlap trick, marking blanks with X, and cross-referencing — a step-by-step guide for adults new to picture logic puzzles.

Puzzle strategy

Mental subtraction tricks

Four tricks — count up, bridge through 10, left to right, round and adjust — that skip paper borrowing and let you subtract fast in your head.

Mental math

Mental division tricks

Four tricks — break the dividend, halve for ÷4 and ÷8, double for ÷5, split the divisor — that skip long division and let you divide fast in your head.

Mental math

Number games for seniors

Eight free number games seniors can play in a browser — no sign-up, no download. Sudoku, Kakuro, Sumplete, Make 10, and more. Start easy and play at your own pace.

Seniors

Quick brain games

Eight free brain games that finish in about five minutes — no sign-up, no download. Make 10, mini Sudoku, memory match, Minesweeper, and more. One round is enough.

Seniors

How to calculate percentages mentally

Calculate percentages without a calculator using two anchors, building blocks, and the flip trick. Tips, discounts, and sales tax — all in your head.

Mental math

How to solve Hashi (Bridges)

Connect numbered islands with logic, not guessing. Find forced bridges first, use the high-number trick for corners and edges, and crack any Hashi grid step by step.

Puzzle strategy

How to solve Masyu

The loop goes straight through white circles but turns beside them, and turns at black circles but runs straight beside them. Two rules, one loop — solved by logic.

Puzzle strategy

How to solve Slitherlink (loop puzzle)

Connect dots into one closed loop using the 0-first habit and corner-3 trick. Work every segment out with logic — no guessing needed.

Puzzle strategy

How to solve Akari (Light Up)

Place light bulbs to illuminate every white square — no guessing. Start with the black 4, apply the diagonal trick, and work each grid out with pure logic.

Puzzle strategy

How to solve Shikaku (Rectangles)

Divide the grid into rectangles where each number is the area. Start with 1s and corners, use the prime-number trick, and solve every grid by logic — not guessing.

Puzzle strategy

Mental addition tricks

Four tricks — left to right, make tens, round and adjust, doubles — that skip paper carrying and let you add fast in your head.

Mental math

How to find any day of the week in your head

Memorize one anchor day and name the weekday for any date. In 2026, dates like 4/4, 6/6, and 12/12 all fall on a Saturday — count in sevens from there.

Mental math

How to play Sumplete

Delete numbers from the grid so each row and column hits its target sum. Start with zero lines, cut overages, then cross-reference to solve without guessing.

Puzzle strategy

Killer Sudoku Combinations

The cage-sum cheat sheet — every unique combination, the full 2-cell chart, and how to use them.

Puzzle strategy

How to solve Nurikabe

The island-and-sea grid puzzle explained: learn the five rules, start with the 1s for free moves, and keep the sea connected — no guessing needed.

Puzzle strategy

Logic puzzles for adults

Compare ten logic puzzles by difficulty, time, and skill — then pick the one that fits your mood and start with Make 10.

Puzzle strategy

How to solve KenKen 6×6 (and larger grids)

Cage candidate lists, the row-sum rule, and naked pairs — the three strategies that make 6×6 and 7×7 KenKen grids click.

Puzzle strategy

Mathdoku vs KenKen vs Calcudoku

Three names, one puzzle. Learn the real differences, the trademark story, and how to solve a 4×4 arithmetic cage grid step by step.

Puzzle strategy