Generally they mean the same but with a slight distinction of meaning. For instance: Mi piace il libro - I like the book. (Literally: The book is pleasing to me.) A me piace il libro - I like the book (I am not sure about you but I at least like it.) Also, "mi" in reflexive sentence = myself. "Me" = to me; me (me = complement object) "Mi lavo" - "I wash myself." "Mi sono lavato" - "I have washed myself" "Me" is a strong pronoun that creates emphasis in the sentence. It is used after preposition or a verb: "Vieni con me" - "Come with me."
In general this is correct, but there is a special case. When you have two clitic object pronouns together: an indirect object and a third person direct object (lo,l',la,li,le) or ne, the indirect object pronoun is transformed:
- mi + l'ha dato = me l'ha dato (to me)
- ti + l'ha dato = te l'ha dato (to you [singular])
- gli + l'ha dato = gliel'ha dato (to him [or to them])
- le + l'ha dato = gliel'ha dato (to her or to you [formal])
- ci + l'ha dato = ce l'ha dato (to us)
- vi + l'ha dato = ve l'ha dato (to you [plural])
- si + l'ha dato = se l'ha dato (3p reflexive, reciprocal, indefinite)
That may well be correct but to doesn't explain why 'me' is wrong in this sentence since the sentence it isn't reflexive and literally means that she gave it (to) me. I thought I understood the difference but this one confuses me, especially since, as the OP pointed out, in the previous example the opposite was marked correct. Anyone else have an explanation?
No, it's "ha dato" because "avere" as the auxiliary verb USUALLY just uses the past participle of "dare" (which is "dato") without changing it to agree with gender or number in a sentence with a direct object. "del dentifricio" = "some toothpaste" is the direct object.
Exceptions: the past participle DOES change for gender and number when "avere" is attached to a clitic or 3rd person direct object pronoun: "l'ho", "l'hai", "l'ha", etc.
" Mi ha dato del dentifricio." He (or she) gave me some toothpaste.
AND "Me l'ha dato." He (or she) gave it to me.
"Mi ha dato la scatola." He (or she) gave me the box. BUT "Me l'ha data." He (or she) gave it to me. (because of direct object "scatola" being feminine.