# SingingNumbers - full content > Generated for AI-agent retrieval. Last updated: 2026-06-21. > > This file mirrors the canonical content of the marketing site in a > flat, machine-readable form. Do not hand-edit; regenerate from the > source pages whenever they change materially. ## What is SingingNumbers? SingingNumbers is a free, fully offline Android calculator that turns every expression into a short melody. Each digit plays a unique musical note. Operators (+ − × ÷) are silent themselves but shape the articulation of the next digit's note (`+` accent, `−` soft, `×` legato, `÷` rest); pressing `=` is also silent and triggers playback of the full expression plus the result as a short melody. Typing `1 + 2 =` therefore produces a three-note melody: the `1`, an accented `2`, and the resulting `3`. Beyond the standard 10-note keypad, a Big Calculator mode extends the input to 24 notes (0-23) for a richer melodic range. Six dedicated screens let you pick a musical scale, an octave range, an instrument timbre, and save expressions you like to replay later. The app declares exactly one Android permission, `VIBRATE`, used for short haptic ticks on button presses. It has no internet permission and cannot connect to a network even if it wanted to. No ads, no analytics, no crash reporting, no telemetry, no in-app purchases, no subscriptions, no account. ## Who is it for? People who learn or teach music and arithmetic together: music teachers, primary-school maths teachers, parents who want a quiet educational toy on a phone or tablet, and adult learners who enjoy a tactile way to explore scales, intervals, and rhythm. The app is rated Teen (13+) on Google Play because it is not enrolled in the Designed for Families programme. It is still suitable for younger users under parental discretion - it collects no data, shows no ads, and has no in-app purchases. ## Features 100% Offline. The manifest declares no INTERNET permission. The operating system cannot open a network socket on behalf of the app. No ads. No banners, interstitials, sponsored content, or affiliate tracking of any kind. Nothing transmitted. No analytics SDK, no crash-reporting service, no telemetry. Calculations never leave the device. Big Calculator. Extends the keypad to 24 notes (0-23) for a richer melodic range, with self-describing multi-digit notes like `[10]`. Pick your sound. Selectable musical scales, octave range, and synthesised instrument timbres on dedicated screens. Save your favourites. Store, rename, and replay expressions from the Saved Calculations screen. Accessibility. TalkBack labels, polite live-regions for state changes, system font scaling, and a built-in dark theme. Free. No subscriptions, no in-app purchases, no trial limits. ## How it works 1. Install SingingNumbers from Google Play (the listing URL will be added here on the Production launch day). 2. Open the app. The Calculator screen is the entry point. 3. Type an expression. Each digit plays a unique musical note; operators (+ − × ÷) are silent but shape the next digit's articulation (accent, soft, legato, rest). 4. Tap `=`. The press itself is silent; it triggers playback of the full expression plus the resulting digits as a short melody, then shows the numeric result. 5. (Optional) Open the drawer to pick a scale, an octave range, an instrument timbre, or to switch on Big Calculator mode. 6. (Optional) Tap Save to keep an expression you like; replay it any time from the Saved Calculations screen. ## Pricing Free. No subscriptions. No in-app purchases. No ads. ## Permissions and data SingingNumbers respects user privacy. Full disclosure is in the privacy policy at https://zadio.bg/singingnumbers/privacy-policy.html. Key facts: - Only one Android permission is declared: `android.permission.VIBRATE`, a "normal" protection-level permission auto-granted by Android and used only for short haptic ticks on button presses. - The INTERNET permission is NOT declared, so the app cannot open a network socket. Nothing your calculations contain ever leaves the device. - A small set of preferences (scale, octave, instrument, language, tempo / rhythm / pitch / haptic, the Big Calculator toggle) and any expressions you choose to save via the Saved screen live on the device only. They are removed when you uninstall the app or use Android's "Clear data" option. ## Frequently asked questions Is the app really free? Yes. SingingNumbers has no subscriptions, no in-app purchases, and no ads. Does it work offline? Always. The app does not declare the INTERNET permission, so it cannot connect to the network even if it wanted to. Does the app collect any data? No. There is no analytics, no crash-reporting service, and no telemetry. The only data stored on your device is your preferences and any expressions you explicitly save via the Saved screen. What is the VIBRATE permission for? Short (~20 ms) haptic ticks when you press a calculator button. `VIBRATE` is a "normal" protection-level permission, so Android grants it automatically - you will never see an install-time or runtime permission prompt for it. The permission only drives the device vibration motor; it cannot read, store, or transmit data. Which Android versions are supported? Android 8.0 (API level 26) and newer, on phones and tablets. The app supports light, dark, and Android 12+ dynamic Material You themes. Is it suitable for children? It is rated Teen (13+) on Google Play. There are no ads, no data collection, and no in-app purchases, so it can be used by younger users under parental discretion. What is "Big Calculator" mode? An extended keypad that exposes 24 notes (0-23) instead of the standard 10, for a richer melodic range. Multi-digit notes are displayed as self-describing chips like `[10]`. What about accessibility? TalkBack labels, polite live-regions for state changes, system font scaling, and a built-in dark theme. ## Legal - Privacy policy: https://zadio.bg/singingnumbers/privacy-policy.html - Terms of service: https://zadio.bg/singingnumbers/terms-of-service.html - Accessibility statement: https://zadio.bg/singingnumbers/accessibility.html ## Contact - Email: app@zadio.bg ## Publisher ZADIO EOOD Ploshtad Han Kubrat 1, Ruse, Bulgaria (EU) EIK: 201209745 VAT: BG201209745 Disputes are exclusively heard before the competent courts seated in Ruse, Bulgaria, without prejudice to mandatory consumer protections.