1Simple or uncomplicated in structure or idea, easy to understand; also describes a person who takes things at face value without much thought.
操作方法はとても単純で、誰でもすぐに覚えられる。
The operating method is very simple, so anyone can learn it quickly.
理由は単純で、ただお金が足りなかっただけだ。
The reason is simple — I just didn't have enough money.
彼女はお世辞にすぐ喜ぶ単純なところがある。
She has a naive side — she gets happy easily at flattery.
この機械の構造は単純だが、壊れにくい。
This machine's structure is simple, but it's hard to break.
単純に計算すれば、一日千円の貯金で一年で36万円になる。
By simple calculation, saving 1000 yen a day comes to 360,000 yen in a year.