What might possibly be the best iOS calculator app, Tydlig, is now free if you have the Apple Store app installed on your device. Tydlig is being touted as a "work hard" app for students going back to school this fall. The offer will run until September 12 and then will be updated to feature the next app. According to Apple:
This month we're celebrating four themes that represent the life of a college student: Get going. Head out. Work hard. Wind down.
This week, work hard with Tydlig, a calculator reimagined to help you with everything from tips and discounts to real-time graphing. Work smarter, not harder, by referencing your previous calculations, and share your work by printing or exporting results as a high-quality PDF.