Zetamac is the free arithmetic drill that became the informal standard for trading interview preparation. This is a drill in the same spirit, plus the parts a plain speed test cannot give you.
Start the Mental Math TrainerFree, runs in your browser, nothing to installIt is free, it starts instantly, and it has no gimmicks — a question appears, you type the answer, the next one loads. That simplicity is exactly why it spread: it mirrors the pressure of a real screen without dressing it up.
It is also the benchmark candidates quote to each other. If someone says they score 45, everyone knows roughly what that means. Any paid platform's mental-math feature is competing with a free tool that already has that shared vocabulary.
| Classic speed drill | This trainer | |
|---|---|---|
| Timed arithmetic | Yes | Yes |
| Configurable operations and ranges | Yes | Yes |
| 80-in-8 exam with −1 penalties | No | Yes |
| Accuracy broken down per operation | No | Yes |
| List of the questions you got wrong | No | Yes |
| Longest correct streak | No | Yes |
The gap that matters most is the second row. A plain speed drill has no penalty for a wrong answer — it simply does not advance. The assessment many firms actually use subtracts a point for a wrong answer and for a skip, and that completely changes how you should play it.
Under +1 / −1 / −1 scoring, a skipped question and a wrong answer cost exactly the same. So there is never a reason to skip. If you are unsure, guess — the guess might be right, and the blank definitely is not.
Candidates who have only ever practised on an unpenalised drill tend to do the opposite. They skip anything uncertain, having trained a habit that costs nothing in practice and a point per question in the real exam.
Most people use a speed drill as a thermometer — they take it, see a number, and learn nothing. Two changes make it training instead.
Isolate your weakest operation. Almost everyone is far slower at division than addition, and a mixed drill lets you hide from it. Turn the others off, drill the weak one, then go back to mixed.
Read your mistakes. The result screen lists the questions you got wrong and your accuracy per operation. Speed gained from skipping careful work on one operation is usually lost twice over in errors.
Ten focused minutes daily beats an hour at the weekend. This is a motor skill more than a mathematical one.
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