Mental Math Tricks vs The observatory

MathMind teaches you real mental math techniques - not gimmicks, not drills you'll forget tomorrow. Learn the same shortcuts used by mathematicians, chess players, and memory athletes to calculate faster than a calculator. 30 PROVEN TRICKS, 7 CATEGORIES: Master techniques across every major area of mental arithmetic: - Multiplication: square numbers ending in 5, multiply by 11, multiply two-digit numbers instantly - Division: divisibility rules, divide by 5, divide by 25 - Squares and roots: square any two-digit number, estimate square roots - Percentages: the percentage flip trick, tips in seconds, compound growth - Fractions: convert, compare, and calculate - Addition and subtraction: round-and-adjust, left-to-right addition - Advanced: day of the week for any date, digit sums, cube estimation THREE WAYS TO LEARN: LEARN - Each trick has a clear explanation, worked examples with step-by-step walkthroughs, and a "Why does this work?" section that shows the underlying math. PRACTICE - Drill any trick with infinite auto-generated problems. Track your accuracy, streak, and solve time as you improve. CHALLENGE - Timed tests across all tricks you've learned. Compete against your own best. Take the Daily Challenge - the same problems for everyone, every day. BUILT FOR REAL PROGRESS: - Speed graphs: watch your solve time drop week by week - Day streaks: build a consistent practice habit - Category breakdown: see exactly where you're strong and where to focus - Combo multipliers: chain correct answers for bonus scoring - Haptic feedback and smooth animations HONEST PRICING: MathMind is free to download with 5 foundational tricks unlocked. Unlock all 30 tricks with a single one-time purchase - no subscriptions, no ads, no data collection, ever. PRIVACY FIRST: Your progress stays on your device. MathMind has no accounts, no sign-ups, no analytics, no trackers, no ads. Nothing leaves your phone, unless you manually share it. Whether you're a student preparing for exams, a professional who wants to run mental calculations in meetings, or just someone who enjoys training their brain - MathMind gives you the tools to think faster. Download and start learning in seconds!

The Observatory is the vocabulary app for curious minds. Every day, a new word is waiting for you. Focus the viewfinder to discover it, learn what it means, how it's used and where it comes from, and then put it to the test. THREE CHALLENGES PER WORD Comprehension, Usage and Mastery: true or false, pick the sentence, spot the odd one, fill in the blank, match the pairs, spelling and stress. Every answer comes with an explanation. Mastery is hard and worth double. YOUR ATLAS Every word you discover becomes a star. Watch your galaxy grow, with a constellation for each category, binary stars that belong to two of them, search and a map. LIBRARY, CATALOGS AND REVIEW All your words in one place. Sort them into your own catalogs, with notes. Review asks you about your words again right before you'd forget them, and it earns you points. KEPLER'S STAR CATALOG Explore regions of the sky and add extra words to your galaxy. 3D COMPANIONS Kelvin the turtle, Vera the octopus, Sagan the fox and their friends react to your answers in 3D. Dress them up with hats, glasses, scarves, things to hold and animated auras, all with the points you earn. STREAKS AND FRIENDS Keep your streak alive, with a reminder before you lose it. Climb the weekly table with your friends and the Best streaks ranking at the space station. IN ENGLISH AND SPANISH More than 20 categories, from everyday language to mythology, philosophy and astronomy, with the whole app in both languages. 3D characters and their wardrobe require a compatible device. On other devices, characters are shown as pictures and the wardrobe is not available. Free to download, with ads. Points are earned by playing; no payment is required at any point.