nokorimono ga aru node, suupaa ni ikanakute mo daijoubu desu.

Because there are leftovers, I don’t need to go to the supermarket.

Breakdown of nokorimono ga aru node, suupaa ni ikanakute mo daijoubu desu.

• です: to be
• に: destination particle
• 行いく: to go
• が: subject particle

Questions & Answers about nokorimono ga aru node, suupaa ni ikanakute mo daijoubu desu.

What does 残り物 mean here?

残り物（のこりもの） means leftovers or things left over.

In this sentence, it most naturally means leftover food. So 残り物がある means there are leftovers.

• 残る = to remain, be left over
• 物 = thing

So the word is literally something like leftover thing(s), but in everyday use it often refers to food left from an earlier meal.

Why is が used after 残り物?

In 残り物がある, the particle が marks the thing that exists.

With ある and いる, Japanese often uses this pattern:

• Noun が ある = there is/are a noun
• Noun が いる = there is/are a living thing

So:

• 残り物がある = there are leftovers

If you used は instead, it would sound more like you are making 残り物 the topic, possibly with some contrast:

• 残り物はある = as for leftovers, there are some

That can work in the right context, but がある is the basic, natural existence pattern.

Why is it ある and not いる?