How the daily challenge works
A new set starts at midnight in your time zone, and everyone gets the same questions for that date. There are three parts, about three minutes in all:
| Part | What you do | Time | Points |
|---|---|---|---|
| Sprint | Arithmetic on the Zetamac default settings: + and − with numbers 2 to 100, × and ÷ up to 12 × 100. Answers submit themselves. | 60 seconds | 1 per problem |
| 80 in 8 mini | 10 multiple-choice questions from the same generator as our Optiver 80 in 8 test: integers, decimals, fractions and missing operands. | 75 seconds | 3 per net point (+1 right, −1 wrong) |
| Interval | One estimate with a lower and an upper bound, scored like the Optiver Intervals round: lower ÷ upper when the true value is inside, 0 when it is not. | 45 seconds | 0 to 10 |
Your score is the sum: sprint solved, plus 3 times the mini net (never below zero), plus the interval points. A tight interval that still contains the answer is worth the most: 90 to 110 scores 8, 50 to 200 scores 3.
What counts
Only your first finished attempt of the day counts for today's board, your streak and the share text. You can play the set again as practice.
Your streak is the number of days in a row with a finished daily challenge. It is saved in this browser, so another device or cleared site data starts a new one.
For longer practice: the full Zetamac game (2 minutes, with a percentile for every run), the full 80 in 8 with a real-test mode, and the number sequence trainer.
Frequently asked questions
When does the daily challenge change?
At midnight in your own time zone. The set is built from the date, so everyone playing on the same date gets the same questions.
Do I need an account?
No. You can play, keep a streak and post to the daily board with just a name. Signed-in players get their display name filled in.
How is the interval question scored?
The same way Optiver scores its Intervals round: if the true value is inside your range, you get your lower bound divided by your upper bound, shown out of 10; if it is outside, you get 0.
Can I play more than once?
Yes, but only the first finished attempt of the day counts for your streak. Later runs are practice.