Where this exercise comes from
“Count down from 100 by sevens” is a well-known task in neuropsychology and medicine. It is used, for example, in short screening tests of attention and memory, where a clinician asks a patient to subtract 7 several times in a row. In the app it is not a diagnosis but a workout: the task loads attention and working memory because you have to remember the current number while doing the subtraction.
Your game score says nothing about your health. If you are worried about your memory or attention, see a doctor.
The correct sequence
100 → 93 → 86 → 79 → 72 → 65 → 58 → 51 → 44 → 37 → 30 → 23 → 16 → 9 → 2.
How to calculate faster
- Subtract 10 and add 3. 86 − 7 = 86 − 10 + 3 = 79. Many people find this easier than borrowing.
- Watch the ones digit. The last digit follows a cycle: 0, 3, 6, 9, 2, 5, 8, 1, 4, 7… If the cycle breaks, you made a mistake.
- Say it aloud or in your head. It helps you keep track of the current number.
- Accuracy first, speed second. A mistake early in the chain costs more than an extra second.
How to make it harder
Once “minus 7” is easy, try other versions in your head: from 200 by 13, from 1,000 by 17. Other games in the section that combine calculation and memory are Quick Math (operations appear one at a time) and Flash Count (the problem is visible for one second).