ZumNum

German numbers are said back to front — 5 716 is “fünftausendsiebenhundertsechzehn”, with the units before the tens — so reading them is one skill and hearing them is another. ZumNum drills the second one: it speaks a number aloud, you type what you heard, and it tells you immediately whether you caught it. The voice is synthesized on the device, so the whole thing works offline, with no ads and no account.

• Hear it, type it A neural voice speaks a number; you type the digits and find out instantly whether you got it right — and if not, what it actually was.
• It learns what trips you up Every answer updates a running score per digit length and per German quirk — the swapped units and tens, the teens, an internal zero. Later rounds drift toward the patterns you keep missing, while still revisiting the ones you have mastered.
• A result that means something The end of a round names a genuine strength and one attainable next step, drawn from your own history rather than a percentage. On iOS 26 that sentence is written on-device by Apple Foundation Models; everywhere else a deterministic version says the same thing.
• The voice runs on your phone Speech is synthesized locally by an on-device neural model — no request leaves the device, and it works with no connection at all.
• Private by design No accounts, no tracking, no ads. Nothing you do leaves your phone.