私は毎日ガムを1パック(or 1袋)全部食べます。
in hiragana: わたし は まいにち がむ を ひとぱっく (or ひとふくろ) ぜんぶ たべます。
*We don't put any spaces between the Japanese words.
*to chew means かむ and you can use it for this translation but たべる sounds more natural, at least yo me.
I hope this was helpful.