"She is a happy child."
Translation:Hun er et glad barn.
But the irregular neuter form "glad" is hardly used at all, so it shouldn't be taught here...
Bad example. No one says "hun/han er et glad barn" in Norway. "Hun er ei glad jente / Han er en glad gutt" is OK. Or you have to use another adjective like "lykkelig", which by the way may be the best translation for happy (glad = glad, happy = lykkelig).