App quits unexpectedly – Nice Calc Review

I rated this 3 stars from my last rating of 5 because the app quits from no reason. While typing numbers at any given time, on my IPad Pro, the app closes and the numbers entered are gone. My Ipad is fully updated and I am using the Premium Version of your app. Please fix this and I will move the rating back to 5 stars. Thank you in advance.
Review by Wagner junior on Nice Calc.