The simplest method I can think of is to make a copy of the document and delete the pages after 70 and then those before 40 from the document.

If your person needs to refer to things by page number, restart the page numbering in the new document to begin at page 40.

But to delete everything before p.40 and after p.70 would also need using click and drag, I assume?

Or, if there is a quicker way?

I need only content of p.40 to p.70 so the file can be attached and sent over to him by his email. Otherwise, the whole document will be too large.