This page answers the questions that come up most often about Residual. If yours is not here: app@goswami.de. General matters are on the support page, data handling in the privacy policy.
Write to app@goswami.de. Please mention the app version (at the bottom of Settings), your iOS version and your device — and for a wrong result, the line exactly as it stands.
Round buttons sit at the top of the sheet. The first on the right opens sheets and settings, the middle one opens sharing.
In the sheet list the gear opens Settings and the arrow icon next to it loads a sheet from a file. Settings are in five groups: Rechnen, Darstellung, Blätter, Eingabe and Sprache & Residual.
Unlike a calculator with a display, nothing disappears in Residual. You type a whole line — 84.50 + 20 % — and the result sits next to it. Change a number in it later and the line recalculates at once.
Every number can carry a label: tap it and give it a name. After that the line reads like a sentence rather than a formula.
84.50 + 20 % is 101.40, not 84.70. The percent sign refers to the number before it, the way you mean it for a markup or a tip.
If you really want to add twenty hundredths, write 84.50 + 0.2.
A line's result can be used in another line — the arcs between lines show those links. Change something at the top and the change runs through every dependent line.
A link that would close a loop (A needs B, B needs A) is refused as you tap it. That is not a bug but the point: a loop would have no result.
Whether the arcs stay visible is set under Settings → Darstellung → Verknüpfungen: Bei Bedarf shows them on tap, Immer leaves them up.
Either works. A comma from dictation, a hardware keyboard or the clipboard becomes the decimal separator as long as the number does not have one yet; after that it separates arguments, as in max(3, 5). Whether thousands are grouped is set under Settings → Tausendertrennung.
You can create as many sheets as you like — one for the project, one for travel costs, one for trying things out. The angle unit (degrees or radians) belongs to the sheet, not to the app as a whole. For the title, Residual suggests names built from the sheet's own labels.
Any line can be drawn as a curve: Residual sweeps one number across a range and reads a dependent line along with it. That shows how a result moves with an assumption. The card can be pulled out to full screen.
With an iCloud account signed in, your sheets are on all your devices. The state is shown under Settings → iCloud-Sync; “aus · kein iCloud-Konto” means no account is signed in on the device. There is no switch in the app — syncing depends on the account alone, and you turn it off in iOS Settings under Apple ID → iCloud.
If two devices changed the same sheet, Residual keeps both versions — the other one appears as a second entry with the device and time in its name. It deliberately does not merge them: better one sheet too many than a line nobody wrote that way.
For conversions Residual downloads the European Central Bank's daily reference rates — at most once per rate day, then from the cache. Offline it keeps calculating with the last state it has and says what date that is. To refresh by hand use Settings → Kurse aktualisieren; a sheet's target currency is set just above under Ergebnisse in.
Receipt scanning is on out of the box: a button for it sits next to the marker on the sheet. Recognition runs on the device; the photo is neither stored nor transmitted anywhere. Only the lines you place end up on the sheet.
If you do not need it, switch it off under Settings → Eingabe → Beleg fotografieren — the button then disappears and the camera is never requested.
The middle round button at the top offers three ways out of a sheet: PDF (with labels and arcs), a .residual sheet file and copy as text.
A .residual file can be opened anywhere again — through Files, AirDrop, a mail attachment or the arrow icon in the sheet list. It always arrives as a new sheet and never overwrites an existing one.
Under Settings → Farbe & Symbol you choose light, dark or system and one of nine accent colours; the app icon on the home screen changes with it. For left-handed use the keyboard can be mirrored under Tastatur links.