nokorimono wo atatamete, bangohan ni tabemasu.

Yes. 残り物（のこりもの） means leftover food or things left over.

In this sentence, it clearly means food left from an earlier meal.

• 残り = what remains
• 物 = thing(s)

So 残り物を温めて means heat up the leftovers.

を marks the direct object of the verb — in other words, the thing the action is done to.

Here, the leftovers are what gets:

• heated: 残り物を温めて
• and also understood as what gets eaten

So 残り物を tells you that the leftovers are the thing being acted on.

The て-form is being used to connect actions.

So:

• 温めて = heat up ... and
• 食べます = eat

Together, the sentence means something like:

• I’ll heat up the leftovers and eat them for dinner.

This use of the て-form often shows:

1. one action happens before the next, or
2. actions are linked in a natural sequence.

Here the sequence is:

1. heat the leftovers
2. eat them

Because Japanese often omits information that is already clear from context.

The full idea is understood as:

• 残り物を温めて、（残り物を）晩ご飯に食べます。

But repeating 残り物を would sound unnecessary here. Once the leftovers have been introduced, Japanese normally leaves them out if they are still the obvious object.

This kind of omission is extremely common in Japanese.

Here, 晩ご飯に means for dinner.

The particle に is being used to show the purpose/role/result of something — what something will serve as.

So:

• 晩ご飯に食べます = eat it for dinner
• literally, something like eat it as dinner / make it my dinner

This is different from using に for a destination like 学校に行く.
Japanese particles often have several related uses, and this is one of them.

Usually, no — not if you want to say for dinner in this sentence.

• 晩ご飯に食べます = eat it for dinner
• 晩ご飯で would not express the same idea naturally here

A helpful way to think about it is:

• に = what it will serve as / what occasion or role it has
• で = location, means, cause, or the setting of an action

So 晩ご飯に食べます means the leftovers will be the dinner.

Because Japanese often leaves out the subject when it is obvious from context.

In English, you usually need to say:

• I will heat up the leftovers and eat them for dinner.

In Japanese, if it is already clear who is speaking or acting, you can just say:

• 残り物を温めて、晩ご飯に食べます。

The implied subject is often I, but Japanese does not have to say it.

Both can mean dinner / evening meal, but the nuance is a little different.

• 晩ご飯（ばんごはん） sounds more everyday, casual, and conversational
• 夕食（ゆうしょく） sounds a bit more formal or neutral

In daily speech, many people would naturally say 晩ご飯.
So this sentence sounds normal and conversational.

The comma helps readability, but it is not always required.

• 残り物を温めて晩ご飯に食べます。
• 残り物を温めて、晩ご飯に食べます。

Both are understandable.

The comma simply makes the pause between the two actions clearer:

1. heat up the leftovers
2. eat them for dinner

Japanese punctuation is often more flexible than English punctuation.

It is very commonly used for food, but not only for food.

温める（あたためる） means to warm / heat something up.
For example:

• スープを温める = warm up soup
• ご飯を温める = heat up rice
• 体を温める = warm your body

In this sentence, it very naturally means to heat up the leftovers, probably so they are ready to eat.

Yes, it is understandable and natural enough for everyday use.

It means:

• I’ll heat up the leftovers and eat them for dinner.

Depending on the situation, native speakers might also say things like:

• 残り物を温めて、晩ご飯にします。
• 残り物を温めて、晩ご飯として食べます。

But the original sentence is perfectly reasonable for a learner to study, especially because it clearly shows:

• object marking with を
• action-linking with て
• に meaning for dinner / as dinner