Double Digits vs 19×19

Answer two-digit multiplication in your head, instantly. Interview math, exam questions, quick estimates at work. When two-digit multiplication gets fast, the time you spent calculating goes back into thinking. Double Digits is a drill focused on one thing: solving two-digit multiplication again and again until it's fast. Use it to prepare for interviews and exams, or as a few minutes of daily brain training. ACE THE NUMBERS IN INTERVIEWS Consulting case interviews and trading firm mental math tests are done without a calculator. When two-digit multiplication comes instantly, you can keep your focus on the problem itself. PREPARE FOR EXAMS Many entrance exams don't allow calculators. Faster arithmetic leaves more time for the hard questions. BE QUICK WITH NUMBERS AT WORK "37 units at $48 each?" Answer on the spot in meetings and negotiations, and sanity-check estimates before you reach for a calculator. A DAILY WORKOUT FOR YOUR BRAIN Two-digit multiplication means holding numbers in your head while you calculate, which makes it an easy daily brain workout. Watch your times drop as you keep at it. PRACTICE FROM JUST 10 PROBLEMS In Practice, choose a number to learn and a range to multiply it by, and start with as few as 10 problems. It begins with 3 × 10–19. Go after your weak numbers and ranges as often as you like. CONQUER EVERY NUMBER FROM 1 TO 99 In Challenge, take on 90 problems: your chosen number times every two-digit number from 10 to 99. Solve them all to clear it, and work toward clearing all 99. SEE YOURSELF IMPROVE Every finished run records your time and adds it to a line chart. A line sloping downward is your progress. The days you practice are recorded too, so you can keep your streak going. COMPETE WITH OTHER PLAYERS Challenge supports Game Center leaderboards, with a separate board for every number, so you can aim for the top on your best numbers. Signing in is optional; every feature works without it. FEATURES - A drill focused on two-digit multiplication - Practice: start with just 10 problems - Challenge: 90 problems for each number from 1 to 99 - Best times and progress charts for each number and range - Daily streak tracking - Game Center leaderboards - Light and dark mode

Build confidence with multiplication from 1 to 19 through short lessons, practice, and review. A 10-DAY LEARNING PLAN Learn 190 fact pairs, organized by calculation method across 10 lessons. Swapping the factors covers all 361 ordered combinations. Explore doubling, breaking numbers into tens and ones, and working back from 20. ASSESSMENT AND REVIEW Start with an optional 20-question assessment. Spaced review uses your answers to bring back facts that need practice, with mistakes and due facts taking priority. FORWARD AND REVERSE PRACTICE Find the product: 12 × 13 = □ Find the factors: 156 = □ × □ Choose either mode or mix them. Factors range from 1 to 19. Both factor orders are included, and reverse questions accept any valid factor pair within that range. YOUR PACE, YOUR TIMER The default is 5 seconds per question. Choose 3, 5, 6, or 10 seconds, or set a limit from 1 to 30 seconds. Practice 20, 50, 100 questions, or the full question bank. Correct answers receive brief feedback before the next question appears automatically. PERSONAL RESULTS Track scores, accuracy, answer time, and individual responses. Compare completed sessions with matching settings on a leaderboard stored on your device. OFFLINE AND SIMPLE Made for iPhone and iPad running iOS 18 or later. No account, ads, in-app purchases, or subscriptions. Available in Simplified Chinese, Traditional Chinese (Hong Kong), English, Japanese, Korean, Arabic, German, Austrian German, French, Polish, Danish, Vietnamese and Thai. Progress and results are stored on your device. In-app cloud sync is not available, and deleting the app may erase your records. The 10-day plan is a course structure, not a guarantee of mastery. Continue practicing and reviewing at your own pace. Now also available in Modern Standard Arabic, with right-to-left layout and selectable numeral styles.