troppo & tanto

Question 1

when does ‘troppo’ agree in gender and number?

Answer 1

ONLY if there is a noun afterwards

Question 2

why doesn’t ‘troppo’ agree in this sentence?:
“ho mangiato troppo”

Answer 2

there is no noun afterwards, so it always stays as ‘troppo’

Question 3

too much

Answer 3

troppo / troppa / troppi / troppe

Question 4

when do these words (molto/tanto/troppo/poco) change to agree in gender and number?

Answer 4

~ only if they are used as adjectives (e.g. mangio moltE banane)
~ they do not change if they are used on their own as adverbs (e.g. mangio molto)