Don't use "both" with a negative.

Today's post is short but important. You can't use "both" when it's connected a verb with "not". Using "not" is a negation.

negation 否定｛ひてい｝［否認｛ひにん｝・反論｛はんろん｝］の言葉｛ことば｝［考え・表現｛ひょうげん｝］◆【用法】可算名詞。
・There are too many negations in the sentence to be understood. : その文には否定表現

× I don't want both of them.
○ I don't want either of them.
× Both of them don't need it.
○ Neither of them need it.

Don't get confused with the difference between negation and a negative meaning (as in, "not good").

○ Neither of them are wrong. = They are both correct.
○ Both of them are wrong. = They are both incorrect.

Both of us, Johnny and I, are from the US. Neither of us drinks. We both have summer birthdays. You can ask both of us questions about English. If your question can't be answered by either of us, I bet there's no answer. Please ask!