Soulver has a number of keyboards that make it easier to do calculations. On iPhone, Swipe to move between Soulver's keyboards in portrait orientation. On iPad, switch to landscape orientation to access the additional keyboards. To get to the standard alphabetical keyboard, tap "ABC" in the bar above the keyboard.

The keys with "..." in the bottom right corner have a popup with additional related keys. Hold down on a button for a second to show the popup.

Tips:

• You can change the default keyboard order in Soulver's settings (on iPhone), as well as disable keyboards you won't use.
• You might find it useful to put your most frequently used keyboards to the before and after the number pad. That way, they'll only be a single swipe away.