CalcRoll Free app for iPhone and iPad

Multiple roles calculator.
・The calculations and results appear to be recorded in the Roll Paper.
・Seems to contain more than one calculator.
・You can calculate tax and units.
・Rewind the roll can be undone.
・You can keyboard layout the to your liking.

◆ The paid version is ad-free, further stability-oriented.

■ Standard configuration
Display digits: 15 digits maximum
Arithmetic functions: arithmetic only
Drum Number: 2
Calculation method: expression calculator
Number of decimal places: 3
Rounding fractions: even rounding (ISO rounding, Bankers rounding)

■ extra
Internal Processing: 60-digit decimal arithmetic (fixed-point system)
Number of drums: Up to 5
Calculation methods: arithmetic formula or expression calculator
Decimal digits: 0 and 5 F (up to 15 digits)
Rounding fractions: seven
Separator: Four
Decimal points: Three