Parallel calc app for iPhone and iPad

For example, you enjoy BBQ with your friends.
The cost is $890.
You want to know the costs per person.

Maybe, you input "890" in your calculator,
and you input "÷".
Next, you want to input how many member enjoy with.
Well,,, 3 classmates in high school, 8 classmates in the college, 2 neighbors, neighbors have family....
You cant use your calculator in this calculation, because your calculator already has value "890".

You may do a sums in your head, or you borrow one more calculator from your friend.
This is nonsense!

This app has 4 calculators in 1 app,
and you can bring the value in one calculator to the other calculator by one operation!

Of course, it is not idiot as simple calculator.

e.g.
1 ÷ 3 × 3 = 1
(Some calculator says it is 0.99999....)
√2 × √2 = 2
(Some calculator says it is 1.99999...., or there is no root key!)