Shift Calc is a calculator which has big buttons, and a shift button to switch to the second screen to input operation buttons.
Because of the big buttons, it's very easy to input numbers, even though you need to push a little more button.
Especially, if you put your iPhone on the desk and use it as a calculator, then you would soon realize that you could put only 3 fingers on the screen of your iPhone.
That's why Shift Calc has only 3 big buttons on the horizontal dimension. It's very comfortable to push buttons without paying too much attentions.
You can also review the history of input and calculation.
I use it everyday for my job as an accountant. Now, it's your time.
SUMMARY OF GOOD POINTS
* Switch screen by Shift button
* Big buttons are comfortable
* Can use either on the desk or on hand
* Calculation history review function
* Memory buttons