Add & Subtract is a quick round of mixed adding and taking away. It trains your number sense: the faster sums like these come to you, the easier every kind of math gets. Math Adapt AI shapes each round to the sums you find hard. The science: The classic workouts.
How do I play Add & Subtract?
- Tap Add & Subtract on the home screen.
- After a 3, 2, 1 countdown, a sum appears. Type the answer on the keypad.
- As soon as you have typed as many digits as the answer has, it is checked: there is no Enter key to press.
- Keep going until the last question. Your time is on the bar at the top, and the next sum shows in grey above the card.
A round is 20 questions unless you change it to 10 or 50 in Settings, under Questions per workout.
What happens when I get one wrong?
The answer shakes and clears, and you try again. Each wrong try adds 5 seconds to your final time. After three wrong tries the right answer shows in red. For many sums you then get See how, a short animation of a quick way to work it out, while the clock waits for you; Skip moves on.
What do the levels ask?
- Easy: adding numbers up to 8, and taking away within 12
- Medium: adding and taking away numbers up to 30
- Hard: adding numbers up to 99, and taking away within 100
- Very Hard: adding numbers from 100 to 299
Taking away never goes below zero. Change the level on the Math Adapt AI card in Settings. Hard and Very Hard are part of Pro. See Math Adapt AI and difficulty levels.
Can I pause a round?
Yes: the pause button at the top left, Esc, or your device's Back button opens the pause sheet with Resume, Restart and Quit to menu. The clock keeps running while you are paused, so a pause cannot be used to work an answer out.
How is my time worked out?
Your FINAL TIME is the time you took plus 5 seconds for every wrong try. The score screen shows your wrong tries, the penalty, your BEST TIME for that level and number of questions (tap it for your top 10), a NEW BEST ribbon when you beat it, your best streak, and a Recent pace line of your last runs: higher means faster. Then Doc gives his verdict. PLAY AGAIN starts another round; MENU goes home.
Best times are kept separately for each level and length, and for keyboard and touch play, so you always compare like with like.
Can I use a keyboard?
Yes. Type digits on the number keys or the number pad, Backspace deletes a digit, Delete or C clears the answer, and Esc pauses. See Keyboard controls.
Is Add & Subtract free?
Yes, at Easy and Medium. Each round counts toward your free workouts. With Pro you get unlimited workouts and the Hard and Very Hard levels.
Any tips?
- Accuracy saves more time than speed: one wrong try costs 5 seconds.
- Learn the Make Tens and Near Doubles methods in Method Lab: they are free.
- Three clean rounds in a row and Doc offers you the next level.
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