Im visually handicapped, and Ive looked all over for a decent, well-designed calculator with the functions I need. The contrast on the button layout is helpful. In earlier versions, I was annoyed by some rather poor VoiceOver support. It seems to have improved greatly, and as a bonus the developer has now added support for the Apple Watch! Whats pleasing is that the Apple Watch support is actually well thought out. It works far better than other calculators Ive tried on it. It was immediately usable and I am highly appreciative of that. Ive finally reached the point where I am deleting the other calculators I use. This app now does it all for me, and does it well.