# Numvolt — Numvolt: mental math trainer for iPhone

Canonical: https://romeoapps.app/en/numvolt/
Updated: 2026-09-07

Open, calculate, understand, repeat. Numvolt turns arithmetic practice into short sessions on your iPhone: a calm mode, timed sprints, a duel on one phone and a ladder from your city to the world.

## At a glance

- Developer: Roméo Gambino (https://apps.apple.com/developer/id1874823696)
- Platform: iPhone (iOS)
- App languages: French, English
- Price: Free, no in-app purchases
- Account: No account required
- Availability: Release pending · Availability may vary by country

## What you can do

- **Take your time** — Zen mode has no timer. Every wrong answer shows the method behind the correction, so you understand before the next question.
- **Sprint against the clock** — Choose 15, 30 or 60 seconds of addition, subtraction, multiplication and division. Your best sprint can join a ladder ranked by city, region, country and world.
- **Duel on one iPhone** — Two players answer the same questions in turn on a single phone. Scores are revealed at the end.

> In preparation. The app is in French and English. Progress stays on your iPhone: no account, no ads, nothing to buy.

## Questions

### Is Numvolt available on the App Store?

Not yet. The app is being prepared for release; this page will show the App Store link when it is published. Availability may vary by country.

### Do I need an account?

No. Progress is stored on your iPhone. Joining the ladder is optional and uses only a nickname, your city and your scores.

### Where is the privacy policy?

It is published on this site: open “App privacy policy” in the footer. In short: no account, no ads, progress stored on your iPhone, optional ladder, anonymous usage counters that can be switched off in Settings.

### How do I type a fraction or a decimal?

Use the / key for a fraction (3/4) and the , key for a decimal (0.75). Equivalent answers are accepted: 2/4, 1/2 and 0.5 are all correct for one half.

### What does the ladder publish?

Only if you join it: your chosen nickname, your city and the region derived from it, and your best score per sprint format. It needs an iCloud account on the iPhone.

### How does the duel work?

Two players answer the same calculations in turn on a single iPhone. Scores are revealed at the end.

### Does Numvolt contain ads or purchases?

No. The app is free, with no in-app purchases, no ads and no account.

### What does it cost?

The App Store and the app show the current price and available purchases in your local currency before confirmation. Trial availability depends on the offer and your eligibility. A free download does not mean every feature is free.

### Is the app available in my language?

These are translated website pages. Check the Languages section of the App Store listing for the app itself. Some content may use a different language.

### How do I manage a subscription?

On iPhone, open Settings, tap your name, then Subscriptions. Select the app to review or cancel an active subscription. Deleting the app does not cancel a subscription.

## Guides

- [How mental arithmetic works in your head, and why some methods are easier](https://romeoapps.app/en/numvolt/mental-math-methods/)
- [A daily mental math routine that actually sticks](https://romeoapps.app/en/numvolt/daily-mental-math-practice/)
- [Mental math techniques worth learning, and how to practise them](https://romeoapps.app/en/numvolt/mental-math-techniques/)

## Support

Gambinoromeo9@gmail.com — https://romeoapps.app/en/numvolt/support/