Soulver

Soulver is a beautiful notepad calculator app that you will love. It has a new kind of interface that is far more useful than a traditional calculator. It lets you use words alongside numbers, so that they make sense and do calculations over multiple lines. Use Soulver for quick calculations, number problems involving variables, unit conversions, and for thinking through problems that involve math.
WHY SOULVER IS BETTER THAN A TRADITIONAL CALCULATOR:
– Instant answers as you type.
– Spread your calculations over multiple lines, and edit mistakes if you make them.
– Reference previous answers by tapping on them. These are live references, like in a spreadsheet.
– Easy percentage calculations using natural phrases like "15% off $350”, or "$250 + 12% tax", or "40 as a % of 390".
– Supports over 150 currencies (including Bitcoin), and has a specially designed currency keyboard for quick conversions.
– Custom variables across all your documents, and a special keyboard for quick access to them.
– All standard math and programming functions, also available on specially designed keyboards.
– Save your calculations into documents, and sync with iCloud between your Mac, iPhone & iPad.