Does anyone know of books which have lots of questions, whose formats are "fill in the holes" type? The same goes for the theorems and exercises. I am looking at pure math, especially Real analysis, Abstract Algebra, Topology, etc.
in calculus I hope this can help you Exercises and Problems in Calculus John M. Erdman Portland State University Version August 1, 2013
c 2010 John M. Erdman Exercises and Problems in Calculus
Putnam and Beyond is a great resource for problems in core undergraduate math. Also, Concrete math is a great book full of problems( it covers the material through problems, so if you cover up the solutions, you have what you looking for.
Concrete Math can be found online, Google it to take a look.