Should I noindex pages with standalone parts of the whole parent blog post?

I have a particular setup on my blog where I make blog posts that consist of 25 items - like "25 things that are this and that...".

Each of the 25 items is unique - created by me. These blog posts aren't paginated but each of the 25 items also has standalone value and therefore is reachable via it's own unique permalink separately from the post to which it belongs.

My question is: should I noindex the separate item pages because they contain the same content as they contain when in the 25 items group in the parent post? Would the separate pages be considered duplicate content?

I prefer to have the blog posts indexed because cumulatively the 25 items offer a better search-ability value.

Thank you.