Simple Basic Calculator ( GST

This is a Simple calculator for basic business operation and daily life use.

Following are the highlight:
1. Calculate small-big all numbers, no limit.
2. Fraction up to 9 decimal places.
3. Four additional Percentage buttons for GST/TAX/VAT etc. calculation, you can edit the percentage value.
4. Extra Buttons: Square, nth power/exponent, square root, nth root, inverse, factorial, percentage, plus-minus for signed negative.
5. Choose decimal and grouping: US-UK like, Indian like, Europe-like
6. Memory buttons for dual calculation.
7. History for rechecking
8. Split-window / multi-window support