teishoku o tabeta ato de kaikei o shitara, omotta yori yasukatta desu.

to be

Breakdown of teishoku o tabeta ato de kaikei o shitara, omotta yori yasukatta desu.

• 安やすい: cheap
• を: direct object particle
• 食たべる: to eat

Questions & Answers about teishoku o tabeta ato de kaikei o shitara, omotta yori yasukatta desu.

Why is 食べた used before あとで instead of 食べて?

Because あとで is attached to the plain past form of a verb when it means after doing X.

So:

• 食べたあとで = after eating
• not 食べてあとで

This is a fixed pattern:

• Vた + あとで = after doing V

Examples:

• 宿題をしたあとで寝る = I’ll sleep after doing my homework.
• 映画を見たあとでご飯を食べた = I ate after watching the movie.

In your sentence, 定食を食べたあとで means after eating the set meal.

What is the difference between あと and あとで here?

In this sentence, あとで means after.

• 食べたあと = after eating / the time after eating
• 食べたあとで = after eating, then...

In many cases, あと and あとで are very similar, and both can often be translated as after. But あとで often feels a little more clearly adverbial, linking to the next action.

So here:

• 定食を食べたあとで会計をした = After eating the set meal, I paid.

Why is there an を after 定食?