Kraepelin addition
Sustained speed and accuracy of continuous mental addition, with a work curve
Rows of single digits. Add each neighbouring pair and enter the last digit of the sum. Each row lasts one minute and then moves on by itself; there is a five-minute rest after fifteen rows. The score is how many correct answers you reach, and the shape of your work curve. Official form timings are not public; this follows the commonly described layout with original digits.
Free run: the first 20 additions
You will sit the first 20 additions of this test and get your score for them. Unlock it for $8.99, or every test for $25, to sit the full paper and see the breakdown behind the score. What unlocking adds
Before you start
- One row of 21 digits, lasting 20 seconds.
- Add the highlighted pair and press the last digit of the sum (7 + 8 = 15, so press 5). Work along the row; the next pair is selected for you.
- Answers cannot be changed, as on paper. There is no backspace, so carry on after a slip rather than stopping. The score is how far you get.
- Leaving this tab voids the attempt, and that includes during the rest.