History calculator -zen- is a revolutionary easy-to-use calculator.

■ You can see the formula.
You can see the expression you are editing. Calculate by pressing "=".

■ Calculate according to operator priority.
Calculate first in parentheses. Multiplication / division is priority to addition / subtraction.

■ Calculation history can be edit.
You can recalculate past calculation contents.
Use the ARROW button to move the cursor, delete numbers at the cursor position, and insert numbers and symbols.

■ Advertisement is displayed.

■Disclaimer
Although I am making every effort to make the calculation results done with this App, I do not guarantee its accuracy. Please understand that I will not assume any responsibility for damage, loss, disadvantage, etc. caused in using this App.