As new member to this forum, I would like to share you my humble contribution to the world of calculators. It is an android app I developed after my experience with calculators during my studies, and I hope it can make computations on such devices easier for some people.

I have tried various scientific pocket calculators. Some I felt were not enough convenient, having inline display and M+ and M- functions, which made solving problems difficult. It needed much re-entering of previous formulas and the limited memory did not help reuse previous results. I find inline edition also very cumbersome, being hard to tell what the formula actually is. On the other hand there was also the big bulky calculators, with natural display and tons of options. I felt those were to complex for me, as I would never use tools like equation solving or matrix resolution (you have to solve those things on paper anyway..). It did not help also that you had to navigate through many menus with the directional keys. Today making these advanced operations on a laptop with a mouse or touch seems to make much more sense to me.

I settled anyway for a calculator of the Casio FX serie (need a pocket calculator for exams ), which I liked for being usable and not too complex. I liked the fact that it had a natural display, that you could move through the formula to edit it and that you could define variables and reuse them in later equations. However, I also felt it was tedious and slow (the calculator only having a slow processor) to edit the formulas. And reuse of previous results was not straightforward : entering Ans, you would get the result of the last equation, but often while solving a problem you would need previous results. Then you would have to go back in the history, re-enter the formula and the ans would update. Alternatively, I would define a variable, but then I would have to place it in the formula and edition was - again - slow.

Now we have smartphones which are powerhouses, so I thought that I could find a good app on them that did better in usability. Well, I was astonished with the number of mere copies of pocket calculators I could find on google play. So I decided to develop my own approach, which went to be a quite interesting design exercise! I tried to ease at maximum the calculation process and the options available had to be "complete" to be useful, while avoiding to put too much stuff almost nobody would ever use.

So now let me talk about the actual APP

I made the app like a sheet, where you can place formulas freely. Results and bits of previous formulas can be dragged to be reused, it's fast and handy. I named these bits "blocks". These blocks can also be saved to a dedicated memory area, so that any result complex formula entered can be reused any time later. Pictures explain it better than my words :

All the details of whats included in the app is precised on the google play page. The free version is available to anyone to use, without ads or time limit, but there is however a limit on the number of formulas you can enter. The app is very useable like that though

I would gladly discuss what you think of current calculators and my approach to them here. Thanks!