Ealculator app for iPhone and iPad

This is a simple calculator for engineers and general users.
The main screen is a regular calculator design.

The Run button has the same color system and has separated the functions of the buttons by color.

Features for general users:
- General calculator function
- Number count function
- Timer function
- Stopwatch function
- Tip (Percent) value calculation function
- Calculate Percent(P(%)) of value rate (X:Y)
- Main screen is simple design for basic calculator .
- copy&paste calculated result
- copy&paste function string or data from/to other apps
- save to history and back from history
- Time calculator (hours between date time, forward(add) or backward hours from date time)
- Unit converter (included it at version 1.1.x)
+ SI Unit
+ Computer : Byte, KByte, ....
+ Temperature : C, F, K
+ Length : mm, cm, m, km, in, ft, yd, mi,cun(寸), chi(尺), bu(步), li(里)...
+ Area : cm^2, m^2, in^2, ft^2, acre, pyeong(평), ...
+ Mass : g, kg, lb, oz, ...
+ Volume : ml, cc, liter, bal,dan(石),hu(斛),dou(斗),sheng(升),ge(合),shao(勺), ...
+ Food : Cups, FL Oz, Pint, Quart, Tbsp, Tsp, ml
+ Speed : mph, km/h,....
+ Decimals: hexa(16), Decimals(10), octal(8), binary(2)


Feature for Engineers:
- convert mac address to integer and backward
(Calculate mac address from known ports mac address)
- Convert IP address to integer and backward
(Find IP address of a node number/Find node number from IP address when the system has serialized IP address)
- Calculate size as a ratio of rectangle
- Find an average value
- convert date time to second and backward
- IP Calculator (CID, Netmask, Network, Nodes, Broadcast, ...)
- Math (cos, sine, tan, arccos, arcsine, arctan, cosh, sinh, tanh, ...)


Features to be added in future versions:
- More mathematical operations
- Enhance math operation