MathX provides a Calculator Widget to easily make calculations from the Today View in the Notification Center.
On 3D Touch devices, press the MathX app icon on the iOS Home screen to Peek at the MathX Today Widget.
Turn Haptic Feedback when typing on or off. On iPhone 7 and iPhone 7 Plus, go to MathX app > Settings > Today Widget.
Turn Keyboard Clicks on or off. Go to MathX > Settings > iMessage app.
Enable Calculator Widget
Swipe down from the top of your screen to access Notification Center. Then tap Edit at the bottom of Today tab, and + to add the Calculator Widget.
Full Scientific Calculator
MathX Today Widget is a full scientific calculator. It provides a numeric and function keyboard.