General synonyms:
* Simply
* Readily
* Effortlessly
* Smoothly
* Without difficulty
* With ease
* Unproblematically
* Conveniently
* Quickly
* Naturally
More specific synonyms:
* For understanding: Clearly, plainly, readily, understandably, transparently
* For physical tasks: Nimbly, effortlessly, smoothly, dexterously
* For mental tasks: Effortlessly, naturally, readily, instinctively, intuitively
* For emotional response: Easily, readily, spontaneously, willingly, freely
Informal synonyms:
* No sweat
* A piece of cake
* No problem
* Like a breeze
* Like shooting fish in a barrel
Choose the best synonym based on the specific context and nuance you want to convey.