-The frequency of mathematical symbols used varies at each stage, from elementary school, middle school, high school to university; The frequency of symbols used for sets, limits, matrices, functions, and each knowledge range is also different.
As the payment methods for iOS and macOS were not unified when this software was first released, xFormula (iOS) and xFormula (macOS) need to be paid separately.
So if you use it for a long time or frequently, it is strongly recommended to create a suitable input symbol keyboard for yourself, which is more efficient and saves more time than a universal keyboard.
This is a paid software and is provided for free download in the hope that users will know what features this software has and whether it is useful before purchasing.
The advantage of separate payment is pricing splitting, which means that if you only have a mobile device and don't have a Mac, you can save on the purchase cost of the Mac.