Large Math Drill vs Yikou

Train Your Brain to Think in Billions. ■ Can your mental math keep up with high-stakes business? Most people freeze when they see numbers like a hundred million or a few trillion—but in boardrooms, pitch decks, and consulting interviews, that's just the starting point. If you can’t quickly estimate and compute large figures on the fly, you’re not just slow—you’re forgettable. This app gives you the edge: a powerful training ground for mastering the kind of numeric fluency that quietly separates decision-makers from everyone else. ■ What does the app do? It’s laser-focused: Choose your unit: Thousand, Million, Billion, Trillion Customize the number types: powers of 10, multiples of 5 Select operation types: Addition, Division, and more Tap Start and answer lightning-fast using a calculator-style interface The questions appear at the top, and your ability to instantly recognize, process, and act on large numbers is tested in real-time. ■ Track your progress, in numbers—not feelings. Forget vague notions of “I think I’m improving.” This app gives you hard data: Daily accuracy and time-per-question charts Mistakes are saved and recycled into focused review drills Compare historical stats to watch both speed and accuracy evolve ■ Why does it work? Forces your working memory to confront upper limits Strengthens mental arithmetic under pressure Encourages structural thinking even in a multiple-choice format ■ Who is this for? Aspiring consultants, analysts, and investment bankers Founders, execs, and anyone making real decisions with real numbers Students prepping for standardized tests, logic interviews, or competitive math Lifelong learners training for cognitive performance and sharper thinking ■ Use it for interview prep, case studies, quant drills, and more "Estimate the future market for a trillion-dollar industry." "Quickly calculate a rough ROI under time pressure." If those questions make you hesitate, you're not ready. This app builds the intuition and reflexes to handle such questions without blinking. It’s a secret weapon for case interviews, mental math assessments, business exams, and anywhere sharp numeric instincts are non-negotiable. ■ Other features Full English unit support: thousand, million, billion, trillion, quadrillion Clean, intuitive interface Customizable sound, color themes, and answer modes ■ Numbers Don’t Lie. Neither Should Your Brain. This isn’t just a calculator. It’s a mental transformation tool. People who speak the language of large numbers tend to get more respect, more responsibility, and more results. So don’t get left behind. Start training today—even one minute a day rewires the way you think.

Learn Mandarin one useful bite at a time. Yikou brings pronunciation, vocabulary, grammar, speaking practice, and short readings into one calm learning path. START WITH THE SOUNDS Explore the four tones, 23 initials, and 24 finals. Tap any sound or example to hear Mandarin audio, then use the tone quiz to check what you recognize. BUILD A PRACTICAL FOUNDATION Work through 30 units with 959 words, lesson texts, short readings, and quizzes. Review 141 grammar points with examples when you need a clearer explanation. SPEAK, LISTEN, AND RESPOND Practice 26 useful phrases and 13 dialogue scenes. On iPhone or iPad, choose the microphone to receive transcription-based, character-level feedback on a phrase you say. KEEP CHINESE CURRENT Browse 28 slang terms and memes, 50 short stories, and 50 original fictional mini-news items created for reading practice. MADE FOR MORE LEARNERS The interface and learning content are available in English, Korean, Japanese, Thai, German, and Russian. Current version: free, with no ads, account, subscription, or in-app purchase. An internet connection is required to load lessons and media.