You will get much better results with MoboMath if you turn off characters and expressions you don't use. The Configuration wizard which runs the first time you start MoboMath is a good place to start, and you can rerun it at any time from the Grammar menu. After running the wizard, you can fine tune your character choices with the Character dialog.
Here is a list of characters you should consider disabling. Don't worry if you want to keep these enabled – MoboMath should perform reasonably well with them, although you may sometimes have to edit an expression to correct an error. In most cases, you should be able to tap the incorrect character to get the correct choice.
The Configuration wizard suggests you disable o, O, l, i and I, but only the one stroke versions of i and I (in other words, an i with a dot or an I with caps on the top and bottom will still be recognized). These characters are highly confusable with 0 and 1. If you disable them, MoboMath will still recognize them as part of function names like log or cos.
The Configuration wizard allows you to turn off all Greek characters. If you do this, MoboMath will still recognize the summation operator 
and the product operator 
.
If you use Greek in your work, consider turning off these characters in the Character dialog if you don't normally use them:
(nu)
(eta)
(omega)
(upper case Pi) - but MoboMath will still recognize products
Greek characters like upper case Alpha that are identical to a standard character, like A, are never enabled.
If you later begin using different symbols in your work, don't forget to reenable any characters you need.