Rising Calculator is a quick and easy-to-use app for iPhone and iPad, the app gives you a calculator to deal with different numbers and calculations based on what you need, this is the Lite version which shows advertisements, you can get the regular version with no Ads and Apple Watch Support.

You can tap any element (number/operation) to adjust, delete, or insert after it. also, double tapping the first element will insert a new element before it, tapping on History button will show you all operation in the current session and upon tapping on any it will select desired equation.