SFX-Calc Support and User Guide

Introduction

SFX-Calc is a calculator app designed for academic, scientific and engineering purpose. The calculator features:

1.	Basic arithmetic calculation: Plus, Minus, Multiply, Divide
2.	Calculation with one operand fixed as constant
3.	Calculation with a non-volatile memory storage
4.	Calculation with 10 volatile memory storage
5.	Fraction and percentage calculation
6.	Linear regression and Statistic calculation
7.	Binary / Octal / Decimal / Hexadecimal calculation
8.	Various functions like Trigonometric, Hyperbolic, Logarithm, Exponential, Power, Root, etc.
9.	UI/UX similar to Casio scientific calculator
10.	Formula calculation including Quadratic formula, Standard Normal Distribution Probability, etc.

Support

If you find any issues or have any suggestions, please feel free to contact me (eefelix@yahoo.com.hk) or post your message on the support forum https://github.com/eefelix/SFX-Calc-Public/issues

Usage

Display

The calculator can display up to 10 main digits + 2 exponential digits in default settings, or up to 13 main digits + 3 exponential digits by turning ON some options from the menu. Various numeric formats can be displayed in different states of operation:

Numeric format	The display will show ...
Integral
Decimal
Exponential
Fractional
Hexadecimal
Error

The display has a top bar to indicate the current state of operation:

When ...	The display will show ...
A non-zero value is stored in the non-volatile memory
The calculation has one operand fixed as constant
Performing Statistic calculation
Performing Linear regression
Performing Binary / Octal / Decimal / Hexadecimal calculation
Performing Trigonometric calculation with different angle unit (DEG / RAD / GRA)
Performing Formula calculation

Key

(1)

All Cancel

Clear the current operation

Clear the fixed constant operand

Clear the display result

Release the error state

Alterative function is to clear the 10 volatile memory spaces in additional to the all cancel functions, or to clear the all the stored data for the linear regression and the statistic calculation

(2)

Clear

Clear the current entry for correction

(3)

Alternative Function

Enable alternative function from other function keys

(4)

Mode Set

Normal computation mode

Base-n mode for Binary / Octal / Decimal / Hexadecimal calculation

Statistic calculation

Linear regression calculation

Trigonometric calculation will be conducted with Degree unit

Trigonometric calculation will be conducted with Radian unit

Trigonometric calculation will be conducted with Gradian unit

Alterative function is to show the formula menu. After choosing the formula from the menu, the formula calculation will be executed

(5)

Digits

Input numerals

Alterative function in normal computation mode is to recall the following scientific constants

	Speed of light = 299792458 ms^-¹
	Planck constant = 6.62607015x10^-34 Js
	Newtonian constant of gravitation = 6.67430x10^-11 m³kg^-¹s^-²
	Elementary charge = 1.602176634x10^-19 C
	Electron mass = 9.1093837015x10^-31 kg
	Atomic mass = 1.66053906660x10^-27 kg
	Avogadro constant = 6.02214076x10²³
	Boltzmann constant = 1.380649x10^-23 JK^-¹
	Coulomb constant = 8.9875517923x10⁹ kgm³s^-²C^-²

Alterative function in statistic calculation mode is to calculate the statistic of the stored data

	The average value of the stored data
	The population standard deviation of the stored data
	The sample standard deviation of the stored data

Alterative function in linear regression calculation mode is to calculate the statistic and the regression parameters of the stored data

	The average value of the x-component of stored data
	The population standard deviation of the x-component of stored data
	The sample standard deviation of the x-component of stored data
	The average value of the y-component of stored data
	The population standard deviation of the y-component of stored data
	The sample standard deviation of the y-component of stored data
	The intercept parameter of linear regression of stored data
	The slope parameter of linear regression of stored data
	The correlation parameter of linear regression of stored data

(6)

Dot

Input the operand value in decimal format

Alternative function is to generate a random value ranging from 0 to 0.999

(7)

Exponent entry

Graphical user interface, text

Description automatically generated

Input exponent of base 10

The value will be displayed in exponential format

Alternative function is to recall the last answer

(8)

Plus

Perform addition of the 1^st (X) and 2^nd (Y) operand:

Tapping twice will store the 1^st (X) operand as constant (C) for subsequent addition:

Alternative function is to find the remainder of the 1^st (X) operand divided by the 2^nd (Y) operand:

(9)

Minus

Perform subtraction of the 1^st (X) and 2^nd (Y) operand:

Tapping twice will store the 1^st (X) operand as constant (C) for subsequent subtraction:

(10)

Multiply

Perform multiplication of the 1^st (X) and 2^nd (Y) operand:

Tapping twice will store the 1^st (X) operand as constant (C) for subsequent multiplication:

Alternative function is to raise the 1^st (X) operand to the power of 2^nd (Y) operand:

(11)

Divide

Perform division of the 1^st (X) and 2^nd (Y) operand:

Tapping twice will store the 1^st (X) operand as constant (C) for subsequent multiplication:

Alternative function is to take 2^nd (Y) operant root of 1^st (X) operand:

(12)

Equal

Conduct the 2 operands calculation and display the result

Alternative function is to conduct percentage, premium, discount calculation

(13)

Recall the constant value pi (3.14 ...)

When the formula calculation is being executed, it is used to enter the input variables and to show the output results. The input variables and the output results will be stored into the volatile memory spaces (from (K0) to (K9)), so that when the formula is invoked next time, then the same calculation can be executed by just pressing this key without entering new values

(14)

Open bracket / Input x-component of data

Open a new bracket to start prioritized calculation. Nesting of up to 99 pairs of brackets are allowed

In the linear regression calculation mode, it is used to enter the x-component of data

(15)

Close bracket / Estimate from linear regression

Close the nearest bracket to finish prioritized calculation

In the linear regression calculation mode, it is used to estimate the y-component for a given x-component, or the alternative function is to estimate the x-component for a given y-component

(16)

Store volatile memory

Store the currently displayed value into one of the 10 volatile memory spaces

The volatile memory space can be selected from (K0) to (K9)

(17)

Recall volatile memory / Shift function in linear regression and statistic calculation mode

Recall the value from one of the 10 volatile memory spaces

The volatile memory space can be selected from (K0) to (K9)

In the statistic calculation mode, it combines with the digit key to calculate the statistic of the stored data

The sum of square of the stored data

The sum of the stored data

The stored data count

In the linear regression mode, it combines with the digit key to calculate the statistic and the regression parameters of the stored data

	The sum of square of the x-component of stored data
	The sum of the x-component of stored data
	The stored data count
	The sum of square of the y-component of stored data
	The sum of the y-component of stored data
	The sum of product of the x-component and y-component of stored data

(18)

Display value in engineering exponential format (forward direction) / Switching between Decimal and Binary in base-n mode

Display value with decimal point shifted and in the form of

Tapping subsequently will display the value in the form of so on

Alternative function is to conduct permutation of the 1^st (X) and 2^nd (Y) operand: For example to calculate , press A picture containing text, sign

Description automatically generated to get the answer

When the calculation mode is base-n, tapping can switch to Decimal and (Alternative function) Binary calculation

(19)

Display value in engineering exponential format (reverse direction) / Switching between Hexadecimal and Octal in base-n mode

Display value with decimal point shifted and in the form of

Tapping subsequently will display the value in the form of so on

Alternative function is to conduct combination of the 1^st (X) and 2^nd (Y) operand: For example to calculate , press A picture containing text, sign

Description automatically generated to get the answer.

When the calculation mode is base-n, tapping can switch to Hexadecimal and (Alternative function) Octal calculation

(20)

Factorial

Calculate the factorial of the 1^st (X) operand

Alternative function is to swap the 1^st (X) and 2^nd (Y) operand in the current calculation

When the calculation mode is base-n, then perform bitwise NOT operation of the 1^st (X) operand

(21)

Reciprocal

Calculate the reciprocal of the 1^st (X) operand

Alternative function is to swap the 1^st (X) and selected volatile memory (K0 to K9)

When the calculation mode is base-n, then perform bitwise AND operation of the 1^st (X) and 2^nd (Y) operand

(22)

Square root

Calculate the square root of the 1^st (X) operand

When the calculation mode is base-n, then perform bitwise OR operation of the 1^st (X) and 2^nd (Y) operand

(23)

Square

Calculate the square of the 1^st (X) operand

When the calculation mode is base-n, then perform bitwise XOR operation of the 1^st (X) and 2^nd (Y) operand

(24)

Common logarithm

Calculate the common logarithm (base 10) of the 1^st (X) operand

Alternative function is to calculate the value of 10 to the power of the 1^st (X) operand

When the calculation mode is base-n, then perform bitwise XNOR operation of the 1^st (X) and 2^nd (Y) operand

(25)

Natural logarithm

Calculate the natural logarithm (base e=2.718...) of the 1^st (X) operand

Alternative function is to calculate the value of e to the power of the 1^st (X) operand

(26)

Fraction

Input the operand value in fractional format

The value will be displayed in fractional format. E.g. represents the fraction value

Alternative function is to calculate the improper fraction of the current fraction

When the calculation mode is base-n, then input numeral A for hexadecimal value

(27)

Degree

Input the degree value in sexagesimal scale. The value will be displayed in decimal format.

Alternative function is to display the value in degree format

When the calculation mode is base-n, then input numeral B for hexadecimal value

(28)

Hyperbolic calculation

Enable hyperbolic calculation with the subsequent key

Calculate the sinh (Alternative function is to calculate the inverse sinh) of the 1^st (X) operand

Calculate the cosh (Alternative function is to calculate the inverse cosh) of the 1^st (X) operand

Calculate the tanh (Alternative function is to calculate the inverse tanh) of the 1^st (X) operand

When the calculation mode is base-n, then input numeral C for hexadecimal value

(29)

Sine

Calculate the sine value of the angle given in the 1^st (X) operand in the current angle unit

Alternative function is to return the angle in the current angle unit from the arc-sine calculation of the 1^st (X) operand

When the calculation mode is base-n, then input numeral D for hexadecimal value

(30)

Cosine

Calculate the cosine value of the angle given in the 1^st (X) operand in the current angle unit

Alternative function is to return the angle in the current angle unit from the arc-cosine calculation of the 1^st (X) operand

When the calculation mode is base-n, then input numeral E for hexadecimal value

(31)

Tangent

Calculate the tangent value of the angle given in the 1^st (X) operand in the current angle unit

Alternative function is to return the angle in the current angle unit from the arc-tangent calculation of the 1^st (X) operand

When the calculation mode is base-n, then input numeral F for hexadecimal value

(32)

Sign

Change the sign of the 1^st (X) operand

When the calculation mode is base-n, then perform 2s complement operation of the 1^st (X) operand for binary / octal / hexadecimal value

(33)

Delete

Delete the previous step(s) of entry

(34)

Non-volatile memory recall

Recall the value from the non-volatile memory (M)

Alterative function is to store the current displayed value into the non-volatile memory (M)

(35)

Non-volatile memory plus / store or delete data in linear regression and statistic calculation mode

Perform addition of the non-volatile memory (M) and 1^st (X) operand:

Alterative function is to perform subtraction of the non-volatile memory (M) and 1^st (X) operand:

In the linear regression and statistic calculation mode, it is used to store the data, or the alternative function is to delete the current value of 1^st (X) operand from the stored data

Other features

The calculator has the following other features:

Copy and Paste number on display

Double tap on the display would pop-up the menu to copy and paste number between other apps in your device

Home screen quick action to copy the last answer

At home screen, long press the app icon would pop-up the quick action menu to copy the last answer from the app so that you may paste the answer to other apps in your device

Haptic Feedback	If this option is ON, then there will be a short vibration whenever a key is pressed
Blinking Feedback	If this option is ON, then there will be a short blinking on the display whenever a key is pressed
Sound	If this option is ON, then there will be a short tock sound whenever a key is pressed
Italic Font	If this option is ON, then the italic font will be used to display the digits on the display
Exp Form Padding	If this option is ON, then the exponential digits will be padded with leading zeros (e.g. will be shown as )
Comma Decimal Point	If this option is ON, then comma will be used as decimal point (e.g. will be shown as )
Thousand Separator	If this option is ON, then a separator will be placed every 3 digits when displaying a large number (e.g. will be shown as if Comma Decimal Point is OFF, or if Comma Decimal Point is ON)
13-Digit Mode	If this option is ON, then the display can show up to 13 main digits instead of 10 main digits with the trade-off of smaller font
3-Exp-Digit Mode	If this option is ON, then the display can show up to 3 exponential digits instead of 2 exponential digits with the trade-off of smaller font

A screenshot of a calculator

Description automatically generated

Limitation

The calculator has the following limitations:

1.	If the calculation result is larger than (in 3-Exp-Digit Mode), or smaller than (in 3-Exp-Digit Mode), then error will be displayed
2.	If the calculation result has absolute value smaller than (in 3-Exp-Digit Mode), then error will be displayed
3.	Nested-bracket can go up-to 99 level
4.	In base-n mode, if 13-Digit Mode is OFF, then the binary value may range from -512 (1000000000_b) to 511 (0111111111_b); the decimal value may range from -9999999999 to 9999999999; the octal value may range from -536870912 (4000000000_o) to 536870911 (3777777777_o); the hexadecimal value may range from -2147483648 (80000000_h) to 2147483647 (7FFFFFFF_h)
5.	In base-n mode, if 13-Digit Mode is ON, then the binary value may range from -4096 (1000000000000_b) to 4095 (0111111111111_b); the decimal value may range from -9999999999999 to 9999999999999; the octal value may range from -274877906944 (4000000000000_o) to 274877906943 (3777777777_o); the hexadecimal value may range from -8796093022208 (80000000000_h) to 8796093022207 (7FFFFFFFFFF_h)