Learn French: Il coupe le melon en deux. - He cuts the melon in two.

In French, the preposition en is used to show the result of a physical transformation or division. When you cut, fold, or break something into pieces, you always use en rather than dans, which is strictly for physical location inside something.

Would I use this exact same French sentence to say "He cuts the melon in half"?

Yes! Even though en deux literally translates to "in two", it is the standard, most natural way to say "in half" when cutting or splitting an object. You do not need to use the French noun for half (la moitié).

How would this sentence change if I wanted to say "He cuts it in two"?

You would replace the noun le melon with the direct object pronoun le. Because French object pronouns must be placed directly before the conjugated verb, the new sentence would be Il le coupe en deux.