TKalk is a free, small and safe open source scientific calculator for Symbian S60-touchscreen devices like the Nokia 5800.

Yet another calculator for Symbian-touchscreen smartphones, why take this one? It offers correct mathematical order of operations, trigonometric functions, logarithm and other standard features plus it is

• free: no costs, no advertising
• small: download size is less than 9 KByte
• safe: Written in HTML/CSS/JavaScript (i. e. no binaries which could include hidden functions), you can just unzip the wgz-package and have a look at the source yourself to check that TKalk doesn't connect to the internet or write anything to your smartphone's memory/filesystem.

Download tkalk.wgz to your device (or to your computer and transfer it to the phone), open the file manager and tap on the file to install. An icon in the program menu will be created.

TKalk V1.2 - 19.08.2012: tkalk.wgz

Colors:
dark grey: standard key
light grey: 2nd function with Inv
violet: edit/mode/calculate
red: clear calculation/display
green: digits

Special keys:
Arrows: move cursor
Del: delete char/function
Prev: recall previous calculation
Clr: clear calculation field
Inv Clr: set display to 0
Inv: 2nd function of key
DRG: degree/radian/gradian
Inv x: store display value into x
Inv y: store display value into y

Functions:
acos(x): arccosine
asin(x): arcsine
atan(x): arctangent
cos(x): cosine
exp(x): e^x
fac(x): factorial
lg(x): logarithm (base 10)
ln(x): logarithm (base e)
log(y,x): logarithm (base y)
pow(x,y): x^y
random(): random value (0-1)
root(y,x): yth root of x
sqr(x): square
sqrt(x): square root
sin(x): sine
tan(x): tangent

Misc:
ans: last result
e: 2.7182818
E: *10^
pi: 3.1415927
x: value stored in x
y: value stored in y

TKalk V0.9 - 27.03.2011: First release
TKalk V1.0 - 11.04.2011: Gradian added, color of 'Clr' changed to red, keys centered
TKalk V1.1 - 13.06.2011: Adapt vertical key size to screen height
TKalk V1.2 - 19.08.2012: Prevent resizing when typing long lines, optical improvements