The word molto is used in two ways

1. as an adverb, the English equivalent of which is the adverb very; when used in this way, the word molto has only one form - molto, molto bene, molto grazie e cosi via

2.as an adjective, the English equivalent of which is much or many; when used in this way, the word molto must agree in number
and gender with the word it modifies; its forms will be molta, molte, molto, molti; for example: molta gente, molti colori, molte persone

To determine if a word such as molto is an adjective or adverb check the word that follows it in the sentence. If it is a noun,
then molto is an adjective, agreeing with the noun. Otherwise, it is an adverb. In this case, no agreement pattern is required.

Adjective ----------------------------------------------- Adverb

Lei ha molti soldi. She has a lot of money. --------- Lui e molto intelligente. He is very intelligent.

poco = a little - pochi = plural of poco

Loro studiano poco. They study little. Ci sono pochi studenti. There are few students.

Likewise, the word troppo is used in two ways

3. as an adverb, the English equivalent of which is "too"; when used in this way, the word troppo has only one form; example:
troppo presto = too fast, troppo lontano = too far

4. as an adjective, the English equivalent of which is "too much", or or "a lot"; when used in this way, the word must agree
in number and gender with the word it modifies; for example: troppe parole,

Ricordati que "purtroppo" means unfortunately.

tanto = so much(a lot) tanti = so many

tanto tempo - a lot of time

tanti amici - many friends

Non e tanto intelligente come suo padre. He's not as intelligent
as his father.

Non e tanto intelligente come suo padre. He's not as intelligent
as his father.
I thought you would say "E meno intelligente del suo padre." Non e vero?

Jeanegina if you want to make clear his father was very intelligent you would say "Non è tanto intelligente come suo padre.
Instead if yo say "È meno intelligente di suo padre" you don't give any clue about his father's intelligence, it's more neutral as a sentence.

Thanks Zidanie. That is a very clear explanation.