Our body weight is six times lighter on the moon than it is on the earth.
Our body weight on the earth is six times as much as it is on the moon.
ーOur body weight is six times lighter on the moon than it is on the earth.
「私たちの体重は月では地球より６倍軽い。」
six times lighter on the moon than it is on the earth で比較することができますよ。
ーOur body weight on the earth is six times as much as it is on the moon.
「私たちの地球上での体重は月面上の６倍になる。」
このように six time as much as を使って逆に言うこともできます。
ご参考まで！
カナダ 
