Question

If this library has 134,000 ​books, find how many books are in the category of reference or other​?

Answer 1

134,000-X=Y

Explanation:

you'll first have to solve how many categories there are, but since we don't know we'll use X, we already know that there is 134,000 books, but we don't know how many books are reference or other, so we use Y to represent that.

so it's

134,000-X=Y

I hope this helps