Simplify the following text for a Grade 11 native English-speaking person.
Original: Unlike physical constants , mathematical constants are defined independently of physical measurements , for example the fine-structure constant , even though dimensionless , is not a mathematical constant as it can not currently be mathematically derived . Some mathematical constants , such as e and Ï , arise in many different contexts .
Simplified: In contrast to physical constants , mathematical constants do not come from physical measurements .