To insert an equation using the keyboard press ALT and then type the equation. For example in the following equation it is preferable to ensure there is a decent amount of space between the maths and the text. To add an equation you compose it in the Keynote equation dialog using LaTeX commands or MathML elements then insert it into your presentation.
These are basically placed on the centre of the page and the equations are important ones that deserve to be.
For example in the following equation it is preferable to ensure there is a decent amount of space between the maths and the text. Meaning the next equation has no integer solutions. Disable mathematical typesetting via the same menu item to see and edit the equations LaTeX or AsciiMath. An inline expression occurs in the middle of the text.